diff --git a/.gitignore b/.gitignore
index b21e3adf..ec86ed25 100644
--- a/.gitignore
+++ b/.gitignore
@@ -13,3 +13,7 @@ server/**/lib/
 server/**/bin/
 server/**/pyvenv.cfg
 __pycache__/
+
+# IDE files
+.idea
+*.iml
\ No newline at end of file
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 75a55d62..5053b6e0 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -1,29 +1,28 @@
 repos:
 
 -   repo: https://github.com/pre-commit/pre-commit-hooks
-    rev: v4.4.0
+    rev: v3.2.0
     hooks:
     -   id: trailing-whitespace
     -   id: end-of-file-fixer
     -   id: check-yaml
     -   id: mixed-line-ending
 
-
 -   repo: https://github.com/Lucas-C/pre-commit-hooks
-    rev: v1.4.2
+    rev: v1.1.9
     hooks:
     -   id: remove-tabs
 
 -   repo: https://github.com/psf/black
-    rev: '23.1.0'
+    rev: 20.8b1
     hooks:
       - id: black
         files: 'server/'
         types: [python]
-        language_version: python3.9
+        language_version: python3.8
 
--   repo: https://github.com/PyCQA/isort
-    rev: '5.12.0'
+-   repo: https://github.com/timothycrosley/isort
+    rev: '5.4.2'
     hooks:
     -   id: isort
         files: 'server/'
@@ -32,8 +31,8 @@ repos:
         additional_dependencies:
         -   toml
 
--   repo: https://github.com/pre-commit/mirrors-prettier
-    rev: v2.7.1
+-   repo: https://github.com/prettier/prettier
+    rev: '2.1.1'
     hooks:
     -   id: prettier
         files: client/js/
@@ -41,7 +40,7 @@ repos:
         args: ['--config', 'client/.prettierrc.yml']
 
 -   repo: https://github.com/pre-commit/mirrors-eslint
-    rev: v8.33.0
+    rev: v7.8.0
     hooks:
     -   id: eslint
         files: client/js/
@@ -49,8 +48,8 @@ repos:
         additional_dependencies:
         -   eslint-config-prettier
 
--   repo: https://github.com/PyCQA/flake8
-    rev: '6.0.0'
+-   repo: https://gitlab.com/pycqa/flake8
+    rev: '3.8.3'
     hooks:
     -   id: flake8
         files: server/szurubooru/
@@ -58,5 +57,44 @@ repos:
         -   flake8-print
         args: ['--config=server/.flake8']
 
+-   repo: local
+    hooks:
+    -   id: docker-build-client
+        name: Docker - build client
+        entry: bash -c 'docker build client/'
+        language: system
+        types: [file]
+        files: client/
+        pass_filenames: false
+
+    -   id: docker-build-server
+        name: Docker - build server
+        entry: bash -c 'docker build server/'
+        language: system
+        types: [file]
+        files: server/
+        pass_filenames: false
+
+    -   id: pytest
+        name: pytest
+        entry: bash -c 'docker run --rm -t $(docker build --target testing -q server/) szurubooru/'
+        language: system
+        types: [python]
+        files: server/szurubooru/
+        exclude: server/szurubooru/migrations/
+        pass_filenames: false
+        stages: [push]
+
+    -   id: pytest-cov
+        name: pytest
+        entry: bash -c 'docker run --rm -t $(docker build --target testing -q server/) --cov-report=term-missing:skip-covered --cov=szurubooru szurubooru/'
+        language: system
+        types: [python]
+        files: server/szurubooru/
+        exclude: server/szurubooru/migrations/
+        pass_filenames: false
+        verbose: true
+        stages: [manual]
+
 fail_fast: true
 exclude: LICENSE.md
diff --git a/README.md b/README.md
index 6a38501c..a86ef795 100644
--- a/README.md
+++ b/README.md
@@ -3,12 +3,12 @@
 Szurubooru is an image board engine inspired by services such as Danbooru,
 Gelbooru and Moebooru dedicated for small and medium communities. Its name [has
 its roots in Polish language and has onomatopeic meaning of scraping or
-scrubbing](https://sjp.pwn.pl/sjp/;2527372). It is pronounced as *shoorubooru*.
+scrubbing](http://sjp.pwn.pl/sjp/;2527372). It is pronounced as *shoorubooru*.
 
 ## Features
 
 - Post content: images (JPG, PNG, GIF, animated GIF), videos (MP4, WEBM), Flash animations
-- Ability to retrieve web video content using [yt-dlp](https://github.com/yt-dlp/yt-dlp)
+- Ability to retrieve web video content using [youtube-dl](https://github.com/ytdl-org/youtube-dl)
 - Post comments
 - Post notes / annotations, including arbitrary polygons
 - Rich JSON REST API ([see documentation](doc/API.md))
diff --git a/client/Dockerfile b/client/Dockerfile
index ea5151fa..3490e7ea 100644
--- a/client/Dockerfile
+++ b/client/Dockerfile
@@ -27,6 +27,8 @@ FROM nginx:alpine as release
 RUN apk --no-cache add dumb-init
 COPY --from=approot / /
 
+RUN chmod +x /docker-start.sh
+
 CMD ["/docker-start.sh"]
 VOLUME ["/data"]
 
diff --git a/client/Dockerfile - Copy b/client/Dockerfile - Copy
new file mode 100644
index 00000000..e51bf646
--- /dev/null
+++ b/client/Dockerfile - Copy	
@@ -0,0 +1,45 @@
+FROM node:lts as builder
+WORKDIR /opt/app
+
+COPY package.json package-lock.json ./
+RUN npm install
+
+COPY . ./
+
+ARG BUILD_INFO="docker-latest"
+ARG CLIENT_BUILD_ARGS="--debug"
+RUN BASE_URL="__BASEURL__" node build.js --gzip ${CLIENT_BUILD_ARGS}
+
+FROM scratch as approot
+
+COPY docker-start.sh /
+
+WORKDIR /etc/nginx
+COPY nginx.conf.docker ./nginx.conf
+
+WORKDIR /var/www
+COPY --from=builder /opt/app/public/ .
+
+
+FROM nginx:alpine as release
+
+RUN apk --no-cache add dumb-init
+COPY --from=approot / /
+
+RUN chmod +x /docker-start.sh
+
+CMD ["/docker-start.sh"]
+VOLUME ["/data"]
+
+ARG DOCKER_REPO
+ARG BUILD_DATE
+ARG SOURCE_COMMIT
+LABEL \
+    maintainer="" \
+    org.opencontainers.image.title="${DOCKER_REPO}" \
+    org.opencontainers.image.url="https://github.com/rr-/szurubooru" \
+    org.opencontainers.image.documentation="https://github.com/rr-/szurubooru/blob/${SOURCE_COMMIT}/doc/INSTALL.md" \
+    org.opencontainers.image.created="${BUILD_DATE}" \
+    org.opencontainers.image.source="https://github.com/rr-/szurubooru" \
+    org.opencontainers.image.revision="${SOURCE_COMMIT}" \
+    org.opencontainers.image.licenses="GPL-3.0"
diff --git a/client/build - Copy.js b/client/build - Copy.js
new file mode 100644
index 00000000..51ef643d
--- /dev/null
+++ b/client/build - Copy.js	
@@ -0,0 +1,424 @@
+#!/usr/bin/env node
+'use strict';
+
+// -------------------------------------------------
+
+const webapp_icons = [
+    { name: 'android-chrome-192x192.png', size: 192 },
+    { name: 'android-chrome-512x512.png', size: 512 },
+    { name: 'apple-touch-icon.png', size: 180 },
+    { name: 'mstile-150x150.png', size: 150 }
+];
+
+const webapp_splash_screens = [
+    { w: 640, h: 1136, center: 320 },
+    { w: 750, h: 1294, center: 375 },
+    { w: 1125, h: 2436, center: 565 },
+    { w: 1242, h: 2148, center: 625 },
+    { w: 1536, h: 2048, center: 770 },
+    { w: 1668, h: 2224, center: 820 },
+    { w: 2048, h: 2732, center: 1024 }
+];
+
+const external_js = [
+    'dompurify',
+    'js-cookie',
+    'marked',
+    'mousetrap',
+    'nprogress',
+    'superagent',
+    'underscore',
+];
+
+const app_manifest = {
+    name: 'szurubooru',
+    icons: [
+        {
+            src: baseUrl() + 'img/android-chrome-192x192.png',
+            type: 'image/png',
+            sizes: '192x192'
+        },
+        {
+            src: baseUrl() + 'img/android-chrome-512x512.png',
+            type: 'image/png',
+            sizes: '512x512'
+        }
+    ],
+    start_url: baseUrl(),
+    theme_color: '#24aadd',
+    background_color: '#ffffff',
+    display: 'standalone'
+}
+
+// -------------------------------------------------
+
+const fs = require('fs');
+const glob = require('glob');
+const path = require('path');
+const util = require('util');
+const execSync = require('child_process').execSync;
+const browserify = require('browserify');
+const chokidar = require('chokidar');
+const WebSocket = require('ws');
+var PrettyError = require('pretty-error');
+var pe = new PrettyError();
+
+function readTextFile(path) {
+    return fs.readFileSync(path, 'utf-8');
+}
+
+function gzipFile(file) {
+    file = path.normalize(file);
+    execSync('gzip -6 -k ' + file);
+}
+
+function baseUrl() {
+    return process.env.BASE_URL ? process.env.BASE_URL : '/';
+}
+
+// -------------------------------------------------
+
+function bundleHtml() {
+    const underscore = require('underscore');
+    const babelify = require('babelify');
+
+    function minifyHtml(html) {
+        return require('html-minifier').minify(html, {
+            removeComments: true,
+            collapseWhitespace: true,
+            conservativeCollapse: true,
+        }).trim();
+    }
+
+    const baseHtml = readTextFile('./html/index.htm')
+        .replace('<!-- Base HTML Placeholder -->', `<base href="${baseUrl()}"/>`);
+    fs.writeFileSync('./public/index.htm', minifyHtml(baseHtml));
+
+    let compiledTemplateJs = [
+        `'use strict';`,
+        `let _ = require('underscore');`,
+        `let templates = {};`
+    ];
+
+    for (const file of glob.sync('./html/**/*.tpl')) {
+        const name = path.basename(file, '.tpl').replace(/_/g, '-');
+        const placeholders = [];
+        let templateText = readTextFile(file);
+        templateText = templateText.replace(
+            /<%.*?%>/ig,
+            (match) => {
+                const ret = '%%%TEMPLATE' + placeholders.length;
+                placeholders.push(match);
+                return ret;
+            });
+        templateText = minifyHtml(templateText);
+        templateText = templateText.replace(
+            /%%%TEMPLATE(\d+)/g,
+            (match, number) => { return placeholders[number]; });
+
+        const functionText = underscore.template(
+            templateText, { variable: 'ctx' }).source;
+
+        compiledTemplateJs.push(`templates['${name}'] = ${functionText};`);
+    }
+    compiledTemplateJs.push('module.exports = templates;');
+
+    fs.writeFileSync('./js/.templates.autogen.js', compiledTemplateJs.join('\n'));
+    console.info('Bundled HTML');
+}
+
+function bundleCss() {
+    const stylus = require('stylus');
+
+    function minifyCss(css) {
+        return require('csso').minify(css).css;
+    }
+
+    let css = '';
+    for (const file of glob.sync('./css/**/*.styl')) {
+        css += stylus.render(readTextFile(file), { filename: file });
+    }
+    fs.writeFileSync('./public/css/app.min.css', minifyCss(css));
+    if (process.argv.includes('--gzip')) {
+        gzipFile('./public/css/app.min.css');
+    }
+
+    fs.copyFileSync(
+        './node_modules/@fortawesome/fontawesome-free/css/all.min.css',
+        './public/css/vendor.min.css');
+    if (process.argv.includes('--gzip')) {
+        gzipFile('./public/css/vendor.min.css');
+    }
+
+    console.info('Bundled CSS');
+}
+
+function minifyJs(path) {
+    return require('terser').minify(
+        fs.readFileSync(path, 'utf-8'), { compress: { unused: false } }).code;
+}
+
+function writeJsBundle(b, path, compress, callback) {
+    let outputFile = fs.createWriteStream(path);
+    b.bundle().on('error', (e) => console.error(pe.render(e))).pipe(outputFile);
+    outputFile.on('finish', () => {
+        if (compress) {
+            fs.writeFileSync(path, minifyJs(path));
+        }
+        callback();
+    });
+}
+
+function bundleVendorJs(compress) {
+    let b = browserify();
+    for (let lib of external_js) {
+        b.require(lib);
+    }
+    if (!process.argv.includes('--no-transpile')) {
+        b.add(require.resolve('babel-polyfill'));
+    }
+    const file = './public/js/vendor.min.js';
+    writeJsBundle(b, file, compress, () => {
+        if (process.argv.includes('--gzip')) {
+            gzipFile(file);
+        }
+        console.info('Bundled vendor JS');
+    });
+}
+
+function bundleAppJs(b, compress, callback) {
+    const file = './public/js/app.min.js';
+    writeJsBundle(b, file, compress, () => {
+        if (process.argv.includes('--gzip')) {
+            gzipFile(file);
+        }
+        console.info('Bundled app JS');
+        callback();
+    });
+}
+
+function bundleJs() {
+    if (!process.argv.includes('--no-vendor-js')) {
+        bundleVendorJs(true);
+    }
+
+    if (!process.argv.includes('--no-app-js')) {
+        let watchify = require('watchify');
+        let b = browserify({ debug: process.argv.includes('--debug') });
+        if (!process.argv.includes('--no-transpile')) {
+            b = b.transform('babelify');
+        }
+        b = b.external(external_js).add(glob.sync('./js/**/*.js'));
+        const compress = !process.argv.includes('--debug');
+        bundleAppJs(b, compress, () => { });
+    }
+}
+
+const environment = process.argv.includes('--watch') ? "development" : "production";
+
+function bundleConfig() {
+    function getVersion() {
+        let build_info = process.env.BUILD_INFO;
+        if (!build_info) {
+            try {
+                build_info = execSync('git describe --always --dirty --long --tags').toString();
+            } catch (e) {
+                console.warn('Cannot find build version');
+                build_info = 'unknown';
+            }
+        }
+        return build_info.trim();
+    }
+    const config = {
+        meta: {
+            version: getVersion(),
+            buildDate: new Date().toUTCString()
+        },
+        environment: environment
+    };
+
+    fs.writeFileSync('./js/.config.autogen.json', JSON.stringify(config));
+    console.info('Generated config file');
+}
+
+function bundleBinaryAssets() {
+    fs.copyFileSync('./img/favicon.png', './public/img/favicon.png');
+    console.info('Copied images');
+
+    fs.copyFileSync('./fonts/open_sans.woff2', './public/webfonts/open_sans.woff2')
+    for (let file of glob.sync('./node_modules/@fortawesome/fontawesome-free/webfonts/*.*')) {
+        if (fs.lstatSync(file).isDirectory()) {
+            continue;
+        }
+        fs.copyFileSync(file, path.join('./public/webfonts/', path.basename(file)));
+    }
+    if (process.argv.includes('--gzip')) {
+        for (let file of glob.sync('./public/webfonts/*.*')) {
+            if (file.endsWith('woff2')) {
+                continue;
+            }
+            gzipFile(file);
+        }
+    }
+    console.info('Copied fonts')
+}
+
+function bundleWebAppFiles() {
+    const Jimp = require('jimp');
+
+    fs.writeFileSync('./public/manifest.json', JSON.stringify(app_manifest));
+    console.info('Generated app manifest');
+
+    Promise.all(webapp_icons.map(icon => {
+        return Jimp.read('./img/app.png')
+            .then(file => {
+                file.resize(icon.size, Jimp.AUTO, Jimp.RESIZE_BEZIER)
+                    .write(path.join('./public/img/', icon.name));
+            });
+    }))
+        .then(() => {
+            console.info('Generated webapp icons');
+        });
+
+    Promise.all(webapp_splash_screens.map(dim => {
+        return Jimp.read('./img/splash.png')
+            .then(file => {
+                file.resize(dim.center, Jimp.AUTO, Jimp.RESIZE_BEZIER)
+                    .background(0xFFFFFFFF)
+                    .contain(dim.w, dim.center,
+                        Jimp.HORIZONTAL_ALIGN_CENTER | Jimp.VERTICAL_ALIGN_MIDDLE)
+                    .contain(dim.w, dim.h,
+                        Jimp.HORIZONTAL_ALIGN_CENTER | Jimp.VERTICAL_ALIGN_MIDDLE)
+                    .write(path.join('./public/img/',
+                        'apple-touch-startup-image-' + dim.w + 'x' + dim.h + '.png'));
+            });
+    }))
+        .then(() => {
+            console.info('Generated splash screens');
+        });
+}
+
+function makeOutputDirs() {
+    const dirs = [
+        './public',
+        './public/css',
+        './public/webfonts',
+        './public/img',
+        './public/js'
+    ];
+    for (let dir of dirs) {
+        if (!fs.existsSync(dir)) {
+            fs.mkdirSync(dir, 0o755);
+            console.info('Created directory: ' + dir);
+        }
+    }
+}
+
+function watch() {
+    let wss = new WebSocket.Server({ port: 8080 });
+    const liveReload = !process.argv.includes('--no-live-reload');
+
+    function emitReload() {
+        if (liveReload) {
+            console.log("Requesting live reload.")
+            wss.clients.forEach((client) => {
+                if (client.readyState === WebSocket.OPEN) {
+                    client.send("reload");
+                }
+            });
+        }
+    }
+
+    chokidar.watch('./fonts/**/*').on('change', () => {
+        try {
+            bundleBinaryAssets();
+            emitReload();
+        } catch (e) {
+            console.error(pe.render(e));
+        }
+    });
+    chokidar.watch('./img/**/*').on('change', () => {
+        try {
+            bundleWebAppFiles();
+            emitReload();
+        } catch (e) {
+            console.error(pe.render(e));
+        }
+    });
+    chokidar.watch('./html/**/*.tpl').on('change', () => {
+        try {
+            bundleHtml();
+        } catch (e) {
+            console.error(pe.render(e));
+        }
+    });
+    chokidar.watch('./css/**/*.styl').on('change', () => {
+        try {
+            bundleCss()
+            emitReload();
+        } catch (e) {
+            console.error(pe.render(e));
+        }
+    });
+
+    bundleBinaryAssets();
+    bundleWebAppFiles();
+    bundleCss();
+    bundleHtml();
+
+    bundleVendorJs(true);
+
+    let watchify = require('watchify');
+    let b = browserify({
+        debug: process.argv.includes('--debug'),
+        entries: ['js/main.js'],
+        cache: {},
+        packageCache: {},
+    });
+
+    b.plugin(watchify);
+
+    if (!process.argv.includes('--no-transpile')) {
+        b = b.transform('babelify');
+    }
+    b = b.external(external_js).add(glob.sync('./js/**/*.js'));
+    const compress = false;
+
+    function bundle(id) {
+        console.info("Rebundling app JS...");
+        let start = new Date();
+        bundleAppJs(b, compress, () => {
+            let end = new Date() - start;
+            console.info('Rebundled in %ds.', end / 1000)
+            emitReload();
+        });
+    }
+
+    b.on('update', bundle);
+    bundle();
+}
+
+// -------------------------------------------------
+
+console.log("Building for '" + environment + "' environment.");
+makeOutputDirs();
+bundleConfig();
+if (process.argv.includes('--watch')) {
+    watch();
+} else {
+    if (!process.argv.includes('--no-binary-assets')) {
+        bundleBinaryAssets();
+    }
+    if (!process.argv.includes('--no-web-app-files')) {
+        bundleWebAppFiles();
+    }
+    if (!process.argv.includes('--no-html')) {
+        bundleHtml();
+    }
+    if (!process.argv.includes('--no-css')) {
+        bundleCss();
+    }
+    if (!process.argv.includes('--no-js')) {
+        bundleJs();
+    }
+}
diff --git a/client/css/comment-control.styl b/client/css/comment-control.styl
index 21bbf728..0d5959bb 100644
--- a/client/css/comment-control.styl
+++ b/client/css/comment-control.styl
@@ -127,10 +127,6 @@ $comment-border-color = #DDD
             color: mix($main-color, $inactive-link-color-darktheme)
 
 .comment-content
-    p
-        word-wrap: normal
-        word-break: break-all
-
     ul, ol
         list-style-position: inside
         margin: 1em 0
diff --git a/client/css/core-general.styl b/client/css/core-general.styl
index d25c5f6e..7e5883aa 100644
--- a/client/css/core-general.styl
+++ b/client/css/core-general.styl
@@ -300,10 +300,10 @@ a .access-key
         background-size: 20px 20px
     img
         opacity: 0
-        width: 100%
+        width: auto
         height: 100%
     video
-        width: 100%
+        width: auto
         height: 100%
 
 .flexbox-dummy
diff --git a/client/css/metric-sorter-view.styl b/client/css/metric-sorter-view.styl
new file mode 100644
index 00000000..5388c6e7
--- /dev/null
+++ b/client/css/metric-sorter-view.styl
@@ -0,0 +1,56 @@
+@import colors
+
+#metric-sorter
+    width: 100%
+    @media (max-width: 1000px)
+        padding: 0 !important
+        background-color: white !important
+        h2
+            display: none
+        .messages .message
+            margin-top: 0.5em
+            margin-bottom: 0
+    form
+        width: 100%
+    .posts-container
+        display: flex
+        flex-wrap: wrap
+        margin-bottom: 1em
+        @media (max-width: 1000px)
+            margin-left: -1em
+            margin-right: -1em
+            margin-top: -1em
+        .left-post-container, .right-post-container
+            flex: 1
+            width: 100%
+    .append
+        color: $inactive-link-color
+    .sorting-buttons
+        display: flex
+        @media (min-width: 1000px)
+            padding: 0 0.5em
+        @media (max-width: 1000px)
+            padding: 0.5em 1em
+            width: 100%
+        .compare-block
+            margin: auto
+            button
+                width: 1.3em
+                height: 1.3em
+                font-size: 200%
+                @media (min-width: 1000px)
+                    padding: 0
+                    padding-top: 0.05em
+                @media (max-width: 1000px)
+                    padding: 0
+                    i
+                        transform: rotate(90deg)
+
+            @media (max-width: 1000px)
+                display: flex
+                .save-btn
+                    margin: auto
+                    margin-right: 1em
+                .skip-btn
+                    margin: auto
+                    margin-left: 1em
diff --git a/client/css/post-list-view.styl b/client/css/post-list-view.styl
index e4f75d5d..ba3b0dfa 100644
--- a/client/css/post-list-view.styl
+++ b/client/css/post-list-view.styl
@@ -56,8 +56,8 @@
 
             .edit-overlay
                 position: absolute
-                top: 0.5em
-                left: 0.5em
+                top: 0em
+                left: 0em
 
                 .tag-flipper
                     display: inline-block
@@ -116,7 +116,7 @@
 
                 .delete-flipper
                     display: inline-block
-                    padding: 0.5em
+                    padding: 10em
                     box-sizing: border-box
                     border: 0
                     &:after
@@ -133,7 +133,7 @@
                             font-family: FontAwesome;
                             content: "\f1f8"; // fa-trash
                     &:not(.delete)
-                        background: rgba(200, 200, 200, 0.7)
+                        background: rgba(200, 200, 200, 0.2)
                         &:after
                             color: white
                             content: '-'
@@ -187,9 +187,6 @@
             vertical-align: top
         @media (max-width: 1000px)
             display: block
-            &.bulk-edit-tags:not(.opened), &.bulk-edit-safety:not(.opened)
-                float: left
-                margin-right: 1em
     input
         margin-bottom: 0.25em
         margin-right: 0.25em
diff --git a/client/css/post-main-view.styl b/client/css/post-main-view.styl
index 1183cce2..7b75606c 100644
--- a/client/css/post-main-view.styl
+++ b/client/css/post-main-view.styl
@@ -15,42 +15,38 @@
             border: 0
             outline: 0
 
-    >.sidebar>nav.buttons, >.content nav.buttons
-        margin-top: 0
-        display: flex
-        flex-wrap: wrap
-        article
-            flex: 1 0 33%
-            a
-                display: inline-block
-                width: 100%
-                padding: 0.3em 0
+        nav.buttons
+            margin-top: 0
+            display: flex
+            flex-wrap: wrap
+            article
+                flex: 1 0 25%
+                a
+                    display: inline-block
+                    width: 100%
+                    padding: 0.3em 0
+                    text-align: center
+                    vertical-align: middle
+                    transition: background 0.2s linear, box-shadow 0.2s linear
+                    &:not(.inactive):hover
+                        background: lighten($main-color, 90%)
+                i
+                    font-size: 140%
                 text-align: center
-                vertical-align: middle
-                transition: background 0.2s linear, box-shadow 0.2s linear
-                &:not(.inactive):hover
-                    background: lighten($main-color, 90%)
-            i
-                font-size: 140%
-            text-align: center
-        @media (max-width: 800px)
-            margin-top: 0.6em
-            margin-bottom: 0.6em
+            @media (max-width: 800px)
+                margin-top: 2em
 
     >.content
         width: 100%
 
     .post-container
-        margin-bottom: 0.6em
+        margin-bottom: 2em
 
         .post-content
             margin: 0
 
-    .after-mobile-controls
-        width: 100%
-
 .darktheme .post-view
-    >.sidebar, >.content
+    >.sidebar
         nav.buttons
             article
                 a:not(.inactive):hover
@@ -60,8 +56,6 @@
 @media (max-width: 800px)
     .post-view
         flex-wrap: wrap
-        >.after-mobile-controls
-            order: 3
         >.sidebar
             order: 2
             min-width: 100%
@@ -119,6 +113,7 @@
         h1
             margin-bottom: 0.5em
         .thumbnail
+            background-position: 50% 30%
             width: 4em
             height: 3em
         li
diff --git a/client/css/post-metric-input.styl b/client/css/post-metric-input.styl
new file mode 100644
index 00000000..2d4046ba
--- /dev/null
+++ b/client/css/post-metric-input.styl
@@ -0,0 +1,49 @@
+@import colors
+
+.metric-controls
+    margin-left: 1.4em
+    display: inline-block
+    color: $inactive-link-color
+
+hr.separator
+    display: none
+
+ul.compact-unset-metrics, ul.compact-post-metrics
+    width: 100%
+    margin: 0.5em 0 0 0
+    padding: 0
+    li
+        margin: 0
+        width: 100%
+        line-height: 140%
+        overflow: hidden
+        text-overflow: ellipsis
+        transition: background-color 0.5s linear
+        a
+            display: inline
+        a:focus
+            outline: 0
+            box-shadow: inset 0 0 0 2px $main-color
+        .remove-metric
+            color: $inactive-link-color
+            unselectable()
+            margin-right: 0.5em
+    i
+        padding-right: 0.4em
+    .metric-bounds
+        color: $inactive-link-color
+        unselectable()
+        font-size: 90%
+        margin-left: 0.7em
+
+ul.compact-post-metrics
+    input[type=number]
+        margin-left: 0.5em
+        margin-bottom: 0.5em
+        width: 4em
+        min-width: 60px
+    label
+        display: none
+    .range-delimiter
+        margin-left: 0.5em
+        color: $inactive-link-color
diff --git a/client/css/settings.styl b/client/css/settings.styl
new file mode 100644
index 00000000..95e037ba
--- /dev/null
+++ b/client/css/settings.styl
@@ -0,0 +1,10 @@
+#settings
+    .uploadSafety
+        &>label
+            width: 100%
+        .radio-wrapper
+            display: flex
+            flex-wrap: wrap
+        .radio-wrapper label
+            flex-grow: 1
+            display: inline-block
\ No newline at end of file
diff --git a/client/css/user-list-view.styl b/client/css/user-list-view.styl
index 64915b4d..f1569f8f 100644
--- a/client/css/user-list-view.styl
+++ b/client/css/user-list-view.styl
@@ -21,11 +21,10 @@
     .details
         font-size: 90%
         line-height: 130%
-    .image
-        margin: 0.25em 0.6em 0.25em 0
     .thumbnail
         width: 3em
         height: 3em
+        margin: 0.25em 0.6em 0 0
 
 .darktheme .user-list
     ul li
diff --git a/client/hooks/build b/client/hooks/build
new file mode 100644
index 00000000..46443f40
--- /dev/null
+++ b/client/hooks/build
@@ -0,0 +1,16 @@
+#!/bin/sh
+
+CLOSEST_VER=$(git describe --tags --abbrev=0 ${SOURCE_COMMIT})
+if git describe --exact-match --abbrev=0 ${SOURCE_COMMIT} 2> /dev/null; then
+    BUILD_INFO="v${CLOSEST_VER}"
+else
+    BUILD_INFO="v${CLOSEST_VER}-edge-$(git rev-parse --short ${SOURCE_COMMIT})"
+fi
+
+echo "Using BUILD_INFO=${BUILD_INFO}"
+docker build \
+    --build-arg BUILD_INFO=${BUILD_INFO} \
+    --build-arg BUILD_DATE=$(date -u +'%Y-%m-%dT%H:%M:%SZ') \
+    --build-arg SOURCE_COMMIT \
+    --build-arg DOCKER_REPO \
+    -f $DOCKERFILE_PATH -t $IMAGE_NAME .
diff --git a/client/hooks/post_push b/client/hooks/post_push
new file mode 100644
index 00000000..1b1e0ad9
--- /dev/null
+++ b/client/hooks/post_push
@@ -0,0 +1,19 @@
+#!/bin/sh
+
+add_tag() {
+    echo "Also tagging image as ${DOCKER_REPO}:${1}"
+    docker tag $IMAGE_NAME $DOCKER_REPO:$1
+    docker push $DOCKER_REPO:$1
+}
+
+CLOSEST_VER=$(git describe --tags --abbrev=0)
+CLOSEST_MAJOR_VER=$(echo ${CLOSEST_VER} | cut -d'.' -f1)
+CLOSEST_MINOR_VER=$(echo ${CLOSEST_VER} | cut -d'.' -f2)
+
+add_tag "${CLOSEST_MAJOR_VER}-edge"
+add_tag "${CLOSEST_MAJOR_VER}.${CLOSEST_MINOR_VER}-edge"
+
+if git describe --exact-match --abbrev=0 2> /dev/null; then
+    add_tag "${CLOSEST_MAJOR_VER}"
+    add_tag "${CLOSEST_MAJOR_VER}.${CLOSEST_MINOR_VER}"
+fi
diff --git a/client/html/compact_metric_list_item.tpl b/client/html/compact_metric_list_item.tpl
new file mode 100644
index 00000000..ddddc33b
--- /dev/null
+++ b/client/html/compact_metric_list_item.tpl
@@ -0,0 +1,26 @@
+<li><!--
+--><% if (ctx.editMode) { %><!--
+    --><a href="<%- ctx.formatClientLink('tag', ctx.tag.names[0]) %>"
+          class="<%= ctx.makeCssName(ctx.tag.category, 'tag') %>"><!--
+        --><i class='fa fa-sliders-h tag-icon'></i><!--
+    --></a><!--
+    --><a href="<%- ctx.formatClientLink('posts', {
+                query: 'metric-' + ctx.escapeTagName(ctx.tag.names[0]) +
+                    ':' + ctx.tag.metric.min + '..' + ctx.tag.metric.max +
+                    ' sort:metric-' + ctx.escapeTagName(ctx.tag.names[0])
+                }) %>"
+          class="<%= ctx.makeCssName(ctx.tag.category, 'tag') %>"><!--
+        --><%- ctx.tag.names[0] %>&#32;<!--
+    --></a><!--
+    --><span class='metric-bounds' data-pseudo-content=
+    '<%- ctx.tag.metric.min %> &mdash; <%- ctx.tag.metric.max %>'></span><!--
+    --><span class='metric-controls'>Set<!--
+        --><a href class='create-exact'> exact</a><!--
+        --><a href class='create-range'> range</a><!--
+        --><a href='<%= ctx.getMetricSorterUrl(ctx.post.id, {
+                    metrics: ctx.tag.names[0],
+                    query: ctx.query}) %>'
+               class='sort'> sort</a><!--
+    --></span><!--
+--><% } %><!--
+--></li>
diff --git a/client/html/compact_post_metric_list_item.tpl b/client/html/compact_post_metric_list_item.tpl
new file mode 100644
index 00000000..aa6da3fe
--- /dev/null
+++ b/client/html/compact_post_metric_list_item.tpl
@@ -0,0 +1,32 @@
+<li><!--
+--><% if (ctx.editMode) { %><!--
+    --><a href class='remove-metric' data-pseudo-content='×'/><!--
+    --><a href="<%- ctx.formatClientLink('posts', {
+                query: 'metric-' + ctx.escapeTagName(ctx.tag.names[0]) +
+                    ':' + ctx.tag.metric.min + '..' + ctx.tag.metric.max +
+                    ' sort:metric-' + ctx.escapeTagName(ctx.tag.names[0])
+                }) %>"
+          class="<%= ctx.makeCssName(ctx.tag.category, 'tag') %>"><!--
+        --><i class='fas fa-angle-right tag-icon'></i><!--
+        --><%- ctx.postMetric.tagName %>:</a><!--
+    --><%= ctx.makeNumericInput({
+           name: 'value',
+           value: ctx.postMetric.value,
+           step: 'any',
+           min: ctx.tag.metric.min,
+           max: ctx.tag.metric.max,
+       }) %><!--
+--><% } else { %><!--
+    --><a href="<%- ctx.formatClientLink('tag', ctx.tag.names[0]) %>"
+          class="<%= ctx.makeCssName(ctx.tag.category, 'tag') %>"><!--
+        --><i class='fas fa-angle-right tag-icon'></i><!--
+    --></a><!--
+    --><a href="<%- ctx.formatClientLink('posts', {
+                query: 'metric-' + ctx.escapeTagName(ctx.tag.names[0]) +
+                    ':' + ctx.tag.metric.min + '..' + ctx.tag.metric.max +
+                    ' sort:metric-' + ctx.escapeTagName(ctx.tag.names[0])
+                }) %>"
+          class="<%= ctx.makeCssName(ctx.tag.category, 'tag') %>"><!--
+        --><%- ctx.postMetric.tagName %>: <%- ctx.postMetric.value || 0 %></a><!--
+--><% } %><!--
+--></li>
diff --git a/client/html/compact_post_metric_range_list_item.tpl b/client/html/compact_post_metric_range_list_item.tpl
new file mode 100644
index 00000000..fd4c40e5
--- /dev/null
+++ b/client/html/compact_post_metric_range_list_item.tpl
@@ -0,0 +1,42 @@
+<li><!--
+--><% if (ctx.editMode) { %><!--
+    --><a class='remove-metric' data-pseudo-content='×'/><!--
+    --><a href="<%- ctx.formatClientLink('posts', {
+                query: 'metric-' + ctx.escapeTagName(ctx.tag.names[0]) +
+                    ':' + ctx.tag.metric.min + '..' + ctx.tag.metric.max +
+                    ' sort:metric-' + ctx.escapeTagName(ctx.tag.names[0])
+                }) %>"
+          class="<%= ctx.makeCssName(ctx.tag.category, 'tag') %>"><!--
+        --><i class='fas fa-arrows-alt-h tag-icon'></i><!--
+        --><%- ctx.postMetricRange.tagName %>:</a><!--
+    --><%= ctx.makeNumericInput({
+           name: 'low',
+           value: ctx.postMetricRange.low,
+           step: 'any',
+           min: ctx.tag.metric.min,
+           max: ctx.tag.metric.max,
+       }) %><!--
+    --><span class='range-delimiter'>&mdash;</span><!--
+    --><%= ctx.makeNumericInput({
+        name: 'high',
+        value: ctx.postMetricRange.high,
+        step: 'any',
+        min: ctx.tag.metric.min,
+        max: ctx.tag.metric.max,
+        }) %><!--
+--><% } else { %><!--
+    --><a href="<%- ctx.formatClientLink('tag', ctx.tag.names[0]) %>"
+          class="<%= ctx.makeCssName(ctx.tag.category, 'tag') %>"><!--
+        --><i class='fas fa-arrows-alt-h tag-icon'></i><!--
+    --></a><!--
+    --><a href="<%- ctx.formatClientLink('posts', {
+                query: 'metric-' + ctx.escapeTagName(ctx.tag.names[0]) +
+                    ':' + ctx.tag.metric.min + '..' + ctx.tag.metric.max +
+                    ' sort:metric-' + ctx.escapeTagName(ctx.tag.names[0])
+                }) %>"
+          class="<%= ctx.makeCssName(ctx.tag.category, 'tag') %>"><!--
+        --><%- ctx.postMetricRange.tagName %>:
+        <%- ctx.postMetricRange.low || 0 %> &mdash; <%- ctx.postMetricRange.high || 0 %><!--
+    --></a><!--
+--><% } %><!--
+--></li>
diff --git a/client/html/help_keyboard.tpl b/client/html/help_keyboard.tpl
index f200ce02..6d919bd2 100644
--- a/client/html/help_keyboard.tpl
+++ b/client/html/help_keyboard.tpl
@@ -19,6 +19,11 @@ shortcuts:</p>
             <td>Go to newer/older page or post</td>
         </tr>
 
+        <tr>
+            <td><kbd>R</kbd></td>
+            <td>Go to random post</td>
+        </tr>
+
         <tr>
             <td><kbd>F</kbd></td>
             <td>Cycle post fit mode</td>
@@ -36,7 +41,7 @@ shortcuts:</p>
 
         <tr>
             <td><kbd>Delete</kbd></td>
-            <td>Delete post (while in edit mode)</td>
+            <td>(In edit mode) delete post</td>
         </tr>
     </tbody>
 </table>
diff --git a/client/html/index.htm b/client/html/index.htm
index 2f0f4e40..00728903 100644
--- a/client/html/index.htm
+++ b/client/html/index.htm
@@ -2,7 +2,7 @@
 <html>
 <head>
     <meta charset='utf-8'/>
-    <meta name='viewport' content='width=device-width, initial-scale=1.0'>
+    <meta name='viewport' content='width=device-width, initial-scale=1, maximum-scale=1'/>
     <meta name='theme-color' content='#24aadd'/>
     <meta name='apple-mobile-web-app-capable' content='yes'/>
     <meta name='apple-mobile-web-app-status-bar-style' content='black'/>
diff --git a/client/html/metric_header.tpl b/client/html/metric_header.tpl
new file mode 100644
index 00000000..a711575d
--- /dev/null
+++ b/client/html/metric_header.tpl
@@ -0,0 +1,11 @@
+<form class='horizontal'>
+    <ul class='metric-list'></ul>
+    <wbr>
+    <%= ctx.makeCheckbox({
+        text: 'Show values on posts',
+        name: 'show-values-on-posts',
+        checked: ctx.showValuesOnPost,
+        class: 'append'}) %>
+    <a class='mousetrap button append close sorting'
+       href="<%= ctx.getMetricSorterUrl('random', ctx.parameters) %>">Start sorting</a>
+</form>
diff --git a/client/html/metric_header_item.tpl b/client/html/metric_header_item.tpl
new file mode 100644
index 00000000..880dfedb
--- /dev/null
+++ b/client/html/metric_header_item.tpl
@@ -0,0 +1,6 @@
+<li class="<%= ctx.makeCssName(ctx.metric.tag.category, 'tag') %><%
+            if (ctx.selected) { %> selected<% } %>">
+    <a href class="<%= ctx.makeCssName(ctx.metric.tag.category, 'tag') %><%
+            if (ctx.selected) { %> selected<% } %>"><%
+        %><%- ctx.metric.tag.names[0] %></a>
+</li>
\ No newline at end of file
diff --git a/client/html/metric_sorter.tpl b/client/html/metric_sorter.tpl
new file mode 100644
index 00000000..3023fbd4
--- /dev/null
+++ b/client/html/metric_sorter.tpl
@@ -0,0 +1,39 @@
+<div class='content-wrapper' id='metric-sorter'>
+    <h2>Sorting metric "<%- ctx.primaryMetric %>"</h2>
+    <form>
+        <div class='posts-container'>
+            <div class='left-post-container'></div>
+            <% if (window.innerWidth <= 1000) { %>
+                <div class='messages'></div>
+            <% } %>
+            <div class='sorting-buttons'>
+                <div class='compare-block'>
+                    <% if (window.innerWidth <= 1000) { %>
+                        <input class='mousetrap save-btn' type='submit' value='Save'>
+                    <% } %>
+                    <button class='compare left-lt-right'>
+                        <i class='fa fa-less-than'></i>
+                    </button>
+                    <button class='compare left-gt-right'>
+                        <i class='fa fa-greater-than'></i>
+                    </button>
+                    <% if (window.innerWidth <= 1000) { %>
+                        <a href class='mousetrap append skip-btn'>Skip</a>
+                    <% } %>
+                </div>
+            </div>
+            <div class='right-post-container'></div>
+        </div>
+
+        <% if (window.innerWidth > 1000) { %>
+            <div class='messages'></div>
+        <% } %>
+
+        <div class='buttons'>
+            <% if (window.innerWidth > 1000) { %>
+                <input class='mousetrap save-btn' type='submit' value='Save'>
+                <a href class='mousetrap append skip-btn'>Skip</a>
+            <% } %>
+        </div>
+    </form>
+</div>
diff --git a/client/html/metric_sorter_side.tpl b/client/html/metric_sorter_side.tpl
new file mode 100644
index 00000000..8d0b010f
--- /dev/null
+++ b/client/html/metric_sorter_side.tpl
@@ -0,0 +1,5 @@
+<% if (ctx.post) { %>
+    <a href='<%= ctx.getPostUrl(ctx.post.id, ctx.parameters) %>'>
+        <div class='post-container'></div>
+    </a>
+<% } %>
diff --git a/client/html/post_main.tpl b/client/html/post_main.tpl
index 84e48b1c..7bf31cc4 100644
--- a/client/html/post_main.tpl
+++ b/client/html/post_main.tpl
@@ -29,7 +29,20 @@
                     <span class='vim-nav-hint'>Next post &gt;</span>
                 </a>
             </article>
-            <% if (ctx.canEditPosts || ctx.canDeletePosts || ctx.canFeaturePosts) { %>
+            <article class='random-post'>
+                <% if (ctx.randomPostId) { %>
+                    <% if (ctx.editMode) { %>
+                        <a rel='next' href='<%= ctx.getPostEditUrl(ctx.randomPostId, ctx.parameters) %>'>
+                    <% } else { %>
+                        <a rel='next' href='<%= ctx.getPostUrl(ctx.randomPostId, ctx.parameters) %>'>
+                    <% } %>
+                <% } else { %>
+                    <a rel='next' class='inactive'>
+                <% } %>
+                    <i class='fa fa-random'></i>
+                    <span class='vim-nav-hint'>Random post</span>
+                </a>
+            </article>
             <article class='edit-post'>
                 <% if (ctx.editMode) { %>
                     <a href='<%= ctx.getPostUrl(ctx.post.id, ctx.parameters) %>'>
@@ -37,13 +50,16 @@
                         <span class='vim-nav-hint'>Back to view mode</span>
                     </a>
                 <% } else { %>
-                    <a href='<%= ctx.getPostEditUrl(ctx.post.id, ctx.parameters) %>'>
-                    <i class='fa fa-pencil'></i>
-                    <span class='vim-nav-hint'>Edit post</span>
+                    <% if (ctx.canEditPosts || ctx.canDeletePosts || ctx.canFeaturePosts) { %>
+                        <a href='<%= ctx.getPostEditUrl(ctx.post.id, ctx.parameters) %>'>
+                    <% } else { %>
+                        <a class='inactive'>
+                    <% } %>
+                        <i class='fa fa-pencil'></i>
+                        <span class='vim-nav-hint'>Edit post</span>
                     </a>
                 <% } %>
             </article>
-            <% } %>
         </nav>
 
         <div class='sidebar-container'></div>
@@ -52,15 +68,13 @@
     <div class='content'>
         <div class='post-container'></div>
 
-        <div class='after-mobile-controls'>
-            <% if (ctx.canCreateComments) { %>
-                <h2>Add comment</h2>
-                <div class='comment-form-container'></div>
-            <% } %>
+        <% if (ctx.canListComments) { %>
+            <div class='comments-container'></div>
+        <% } %>
 
-            <% if (ctx.canListComments) { %>
-                <div class='comments-container'></div>
-            <% } %>
-        </div>
+        <% if (ctx.canCreateComments) { %>
+            <h2>Add comment</h2>
+            <div class='comment-form-container'></div>
+        <% } %>
     </div>
 </div>
diff --git a/client/html/post_metric_input.tpl b/client/html/post_metric_input.tpl
new file mode 100644
index 00000000..b3240629
--- /dev/null
+++ b/client/html/post_metric_input.tpl
@@ -0,0 +1,5 @@
+<div class='metric-input'>
+    <ul class='compact-unset-metrics'></ul>
+    <hr class='separator'>
+    <ul class='compact-post-metrics'></ul>
+</div>
diff --git a/client/html/post_readonly_sidebar.tpl b/client/html/post_readonly_sidebar.tpl
index 60efc26a..0f93ae3b 100644
--- a/client/html/post_readonly_sidebar.tpl
+++ b/client/html/post_readonly_sidebar.tpl
@@ -17,8 +17,8 @@
                     'video/mp4': 'MPEG-4',
                     'video/quicktime': 'MOV',
                     'application/x-shockwave-flash': 'SWF',
-                }[ctx.post.mimeType] %><!--
-            --></a>
+                }[ctx.post.mimeType] %>
+            </a>
             (<%- ctx.post.canvasWidth %>x<%- ctx.post.canvasHeight %>)
             <% if (ctx.post.flags.length) { %><!--
                 --><% if (ctx.post.flags.includes('loop')) { %><i class='fa fa-repeat'></i><% } %><!--
@@ -99,10 +99,10 @@
                         --><% if (ctx.canListPosts) { %><!--
                             --><a href='<%- ctx.formatClientLink('posts', {query: ctx.escapeTagName(tag.names[0])}) %>' class='<%= ctx.makeCssName(tag.category, 'tag') %>'><!--
                         --><% } %><!--
-                            --><%- ctx.getPrettyName(tag.names[0]) %><!--
+                            --><%- ctx.getPrettyName(tag.names[0]) %>&#32;<!--
                         --><% if (ctx.canListPosts) { %><!--
                             --></a><!--
-                        --><% } %>&#32;<!--
+                        --><% } %><!--
                         --><span class='tag-usages' data-pseudo-content='<%- tag.postCount %>'></span><!--
                     --></li><!--
                 --><% } %><!--
diff --git a/client/html/posts_header.tpl b/client/html/posts_header.tpl
index 77d16ed7..c4d584d3 100644
--- a/client/html/posts_header.tpl
+++ b/client/html/posts_header.tpl
@@ -4,6 +4,10 @@
         %><wbr/><%
         %><input class='mousetrap' type='submit' value='Search'/><%
         %><wbr/><%
+        %><button id='randomize-button' class='icon-button'><%
+            %><i class="fa fa-random"><%
+        %></button><%
+        %><wbr/><%
         %><% if (ctx.enableSafety) { %><%
             %><input data-safety=safe type='button' class='mousetrap safety safety-safe <%- ctx.settings.listPosts.safe ? '' : 'disabled' %>'/><%
             %><input data-safety=sketchy type='button' class='mousetrap safety safety-sketchy <%- ctx.settings.listPosts.sketchy ? '' : 'disabled' %>'/><%
@@ -16,6 +20,7 @@
         %><form class='horizontal bulk-edit bulk-edit-tags'><%
             %><span class='append hint'>Tagging with:</span><%
             %><a href class='mousetrap button append open'>Mass tag</a><%
+            %><wbr/><%
             %><%= ctx.makeTextInput({name: 'tag', value: ctx.parameters.tag}) %><%
             %><input class='mousetrap start' type='submit' value='Start tagging'/><%
             %><a href class='mousetrap button append close'>Stop tagging</a><%
diff --git a/client/html/similar_post_item.tpl b/client/html/similar_post_item.tpl
new file mode 100644
index 00000000..7203b1e7
--- /dev/null
+++ b/client/html/similar_post_item.tpl
@@ -0,0 +1,5 @@
+<li>
+    <a href='<%= ctx.getPostUrl(ctx.id, ctx.parameters) %>'>
+        <%= ctx.makeThumbnail(ctx.thumbnailUrl) %>
+    </a>
+</li>
diff --git a/client/html/tag_metric.tpl b/client/html/tag_metric.tpl
new file mode 100644
index 00000000..3f06d0c0
--- /dev/null
+++ b/client/html/tag_metric.tpl
@@ -0,0 +1,40 @@
+<div class='tag-metric'>
+    <form class='horizontal edit-metric'>
+        <div class='metric-bounds-edit'>
+            <%= ctx.makeNumericInput({
+                text: 'Minimum',
+                name: 'metric-min',
+                value: ctx.metricMin,
+                step: 'any',
+                readonly: !ctx.canEditMetricBounds,
+            }) %>
+            <%= ctx.makeNumericInput({
+                text: 'Maximum',
+                name: 'metric-max',
+                value: ctx.metricMax,
+                step: 'any',
+                readonly: !ctx.canEditMetricBounds,
+            }) %>
+        </div>
+
+        <% if (ctx.tag.metric && ctx.canDeleteMetric) { %>
+        <div class='confirmation'>
+            <%= ctx.makeCheckbox({name: 'confirm-delete',
+                text: 'I confirm that I want to delete this metric.'}) %>
+        </div>
+        <% } %>
+
+        <div class='messages'></div>
+
+        <div class='buttons'><!--
+            --><% if (!ctx.tag.metric && ctx.canCreateMetric) { %><!--
+                --><input type='submit' value='Create metric'/><!--
+            --><% } else if (ctx.tag.metric && ctx.canEditMetricBounds) { %><!--
+                --><input type='submit' value='Update metric'/><!--
+            --><% } %><!--
+            --><% if (ctx.tag.metric && ctx.canDeleteMetric) { %><!--
+                --><input type='button' name='delete' class='delete' value='Delete metric'/><!--
+            --><% } %>
+        </div>
+    </form>
+</div>
diff --git a/client/html/user_registration.tpl b/client/html/user_registration.tpl
index a6d291f4..debaa57d 100644
--- a/client/html/user_registration.tpl
+++ b/client/html/user_registration.tpl
@@ -23,6 +23,15 @@
                     pattern: ctx.passwordPattern,
                 }) %>
             </li>
+            <li>
+                <%= ctx.makeCodeInput({
+                    text: 'Entry code',
+                    name: 'code',
+                    placeholder: 'Secret code',
+                    required: true,
+                    pattern: ctx.codePattern,
+                }) %>
+            </li>
             <li>
                 <%= ctx.makeEmailInput({
                     text: 'Email',
diff --git a/client/js/api.js b/client/js/api.js
index 5bde6d81..6cc091ab 100644
--- a/client/js/api.js
+++ b/client/js/api.js
@@ -15,6 +15,7 @@ class Api extends events.EventTarget {
         this.user = null;
         this.userName = null;
         this.userPassword = null;
+        this.userCode = null;
         this.token = null;
         this.cache = {};
         this.allRanks = [
@@ -92,6 +93,10 @@ class Api extends events.EventTarget {
         return remoteConfig.passwordRegex;
     }
 
+    getCodeRegex() {
+        return remoteConfig.codeRegex;
+    }
+
     getUserNameRegex() {
         return remoteConfig.userNameRegex;
     }
diff --git a/client/js/controllers/metric_sorter_contoller.js b/client/js/controllers/metric_sorter_contoller.js
new file mode 100644
index 00000000..e7a8d761
--- /dev/null
+++ b/client/js/controllers/metric_sorter_contoller.js
@@ -0,0 +1,187 @@
+'use strict';
+
+const api = require('../api.js');
+const router = require('../router.js');
+const views = require('../util/views.js');
+const topNavigation = require('../models/top_navigation.js');
+const Post = require('../models/post.js');
+const PostMetric = require('../models/post_metric.js');
+const PostMetricRange = require('../models/post_metric_range.js');
+const PostList = require('../models/post_list.js');
+const MetricSorterView = require('../views/metric_sorter_view.js');
+const EmptyView = require('../views/empty_view.js');
+
+const LEFT = 'left';
+const RIGHT = 'right';
+
+class MetricSorterController  {
+    constructor(ctx) {
+        if (!api.hasPrivilege('posts:view') ||
+            !api.hasPrivilege('metrics:edit:posts')) {
+            this._view = new EmptyView();
+            this._view.showError('You don\'t have privileges to edit post metric values.');
+            return;
+        }
+
+        topNavigation.activate('posts');
+        topNavigation.setTitle('Sorting metrics');
+
+        this._ctx = ctx;
+        this._metricNames = (ctx.parameters.metrics || '')
+            .split(' ')
+            .filter(m => m);
+        if (!this._metricNames.length) {
+            this._view = new EmptyView();
+            this._view.showError('No metrics selected');
+            return;
+        }
+        this._primaryMetricName = this._metricNames[0];
+
+        this._view = new MetricSorterView({
+            primaryMetric: this._primaryMetricName,
+            greaterPost: RIGHT,
+        });
+        this._view.addEventListener('submit', e => this._evtSubmit(e));
+        this._view.addEventListener('skip', e => this._evtSkip(e));
+        this._view.addEventListener('changeMetric', e => this._evtChangeMetric(e));
+
+        if (ctx.parameters.id === 'random') {
+            this.startSortingRandomPost();
+        } else {
+            this.startSortingPost(ctx.parameters.id);
+        }
+    }
+
+    startSortingPost(id) {
+        this._view.clearMessages();
+        this._foundExactValue = false;
+        Post.get(id).then(post => {
+            this._unsortedPost = post;
+            this._view.installLeftPost(post);
+            this.reloadMedianPost();
+        }).catch(error => {
+            this._view.showError(error.message)
+        });
+    }
+
+    startSortingRandomPost() {
+        this._view.clearMessages();
+        this._getRandomUnsortedPostId().then(id => {
+            this._ctx.parameters.id = id;
+            router.replace(views.getMetricSorterUrl(id, this._ctx.parameters));
+            this.startSortingPost(id);
+        }).catch(error => {
+            this._view.showError(error.message)
+        });
+    }
+
+    reloadMedianPost() {
+        const metricName = this._primaryMetricName;
+        let range = this._getOrCreateRange(this._unsortedPost, metricName);
+        this._tryGetMedianPost(metricName, range).then(medianResponse => {
+            if (medianResponse.post) {
+                this._sortedPost = medianResponse.post;
+                this._view.installRightPost(this._sortedPost);
+            } else {
+                // No existing metrics, apply the median value
+                this._foundExactValue = true;
+                let exactValue = (medianResponse.range.low + medianResponse.range.high) / 2;
+                this._view.showSuccess(`Found exact value: ${exactValue}`);
+                this._setExactMetric(this._unsortedPost, metricName, exactValue);
+                //TODO: maybe allow to set exact value?
+            }
+        }).catch(error => {
+            this._view.showError(error.message)
+        });
+    }
+
+    _getRandomUnsortedPostId() {
+        let unsetMetricsQuery = this._metricNames
+            .map(m => `${m} -metric:${m}`)
+            .join(' ');
+        let filterQuery = this._ctx.parameters.query || '';
+        let unsetFullQuery = `${filterQuery} ${unsetMetricsQuery} sort:random`;
+
+        return PostList.search(unsetFullQuery,
+                this._ctx.parameters.skips || 0, 1, ['id']).then(response => {
+            if (!response.results.length) {
+                return Promise.reject(new Error('No posts found'));
+            } else {
+                return Promise.resolve(response.results.at(0).id);
+            }
+        });
+    }
+
+    _tryGetMedianPost(metric, range) {
+        let low = range.low + 0.000000001;
+        let high = range.high - 0.000000001;
+        let median_query = `metric-${metric}:${low}..${high} sort:metric-${metric}`;
+        return PostList.getMedian(median_query, []).then(response => {
+            return Promise.resolve({
+                range: range,
+                post: response.results.at(0)
+            });
+        });
+    }
+
+    _getOrCreateRange(post, metricName) {
+        let range = post.metricRanges.findByTagName(metricName);
+        if (!range) {
+            let tag = post.tags.findByName(metricName);
+            range = PostMetricRange.create(post.id, tag);
+            post.metricRanges.add(range);
+        }
+        return range;
+    }
+
+    _setExactMetric(post, metricName, value) {
+        let range = post.metricRanges.findByTagName(metricName);
+        if (!range) {
+            post.metricRanges.remove(range);
+        }
+        let tag = post.tags.findByName(metricName);
+        let exactMetric = PostMetric.create(post.id, tag);
+        exactMetric.value = value;
+        post.metrics.add(exactMetric);
+    }
+
+    _evtSubmit(e) {
+        let range = this._getOrCreateRange(this._unsortedPost, this._primaryMetricName);
+        if (this._foundExactValue) {
+            this._unsortedPost.metricRanges.remove(range);
+        } else {
+            let medianValue = this._sortedPost.metrics.findByTagName(this._primaryMetricName).value;
+            if (e.detail.greaterPost === LEFT) {
+                range.low = medianValue;
+            } else {
+                range.high = medianValue;
+            }
+        }
+        this._unsortedPost.save().then(() => {
+            if (this._foundExactValue) {
+                this.startSortingRandomPost();
+            } else {
+                this.reloadMedianPost();
+            }
+        }, error => {
+            this._view.showError(error.message)
+        });
+    }
+
+    _evtSkip(e) {
+        this._ctx.parameters.skips = (this._ctx.parameters.skips || 0) + 1;
+        this.startSortingRandomPost();
+    }
+
+    _evtChangeMetric(e) {
+        // this._primaryMetricName = e.detail.metricName;
+    }
+}
+
+module.exports = router => {
+    router.enter(
+        ['post', ':id', 'metric-sorter'],
+        (ctx, next) => {
+            ctx.controller = new MetricSorterController(ctx);
+        });
+};
diff --git a/client/js/controllers/pool_controller.js b/client/js/controllers/pool_controller.js
index f49827fe..ad0b9561 100644
--- a/client/js/controllers/pool_controller.js
+++ b/client/js/controllers/pool_controller.js
@@ -91,16 +91,16 @@ class PoolController {
     _evtUpdate(e) {
         this._view.clearMessages();
         this._view.disableForm();
-        if (e.detail.names !== undefined && e.detail.names !== null) {
+        if (e.detail.names !== undefined) {
             e.detail.pool.names = e.detail.names;
         }
-        if (e.detail.category !== undefined && e.detail.category !== null) {
+        if (e.detail.category !== undefined) {
             e.detail.pool.category = e.detail.category;
         }
-        if (e.detail.description !== undefined && e.detail.description !== null) {
+        if (e.detail.description !== undefined) {
             e.detail.pool.description = e.detail.description;
         }
-        if (e.detail.posts !== undefined && e.detail.posts !== null) {
+        if (e.detail.posts !== undefined) {
             e.detail.pool.posts.clear();
             for (let postId of e.detail.posts) {
                 e.detail.pool.posts.add(
diff --git a/client/js/controllers/pool_list_controller.js b/client/js/controllers/pool_list_controller.js
index a66f8163..91d655c5 100644
--- a/client/js/controllers/pool_list_controller.js
+++ b/client/js/controllers/pool_list_controller.js
@@ -43,8 +43,6 @@ class PoolListController {
         this._headerView.addEventListener(
             "submit",
             (e) => this._evtSubmit(e),
-        );
-        this._headerView.addEventListener(
             "navigate",
             (e) => this._evtNavigate(e)
         );
diff --git a/client/js/controllers/post_list_controller.js b/client/js/controllers/post_list_controller.js
index fdb7b844..80348619 100644
--- a/client/js/controllers/post_list_controller.js
+++ b/client/js/controllers/post_list_controller.js
@@ -147,10 +147,11 @@ class PostListController {
             },
             requestPage: (offset, limit) => {
                 return PostList.search(
-                    this._ctx.parameters.query,
-                    offset,
-                    limit,
-                    fields
+                    this._ctx.parameters.query, 
+                    offset, 
+                    limit, 
+                    fields, 
+                    this._ctx.parameters.cachenumber
                 );
             },
             pageRenderer: (pageCtx) => {
diff --git a/client/js/controllers/post_main_controller.js b/client/js/controllers/post_main_controller.js
index bd338129..617418d5 100644
--- a/client/js/controllers/post_main_controller.js
+++ b/client/js/controllers/post_main_controller.js
@@ -51,6 +51,9 @@ class PostMainController extends BasePostController {
                     nextPostId: aroundResponse.next
                         ? aroundResponse.next.id
                         : null,
+                    randomPostId: aroundResponse.random 
+                        ? aroundResponse.random.id
+                        : null,
                     canEditPosts: api.hasPrivilege("posts:edit"),
                     canDeletePosts: api.hasPrivilege("posts:delete"),
                     canFeaturePosts: api.hasPrivilege("posts:feature"),
@@ -169,22 +172,22 @@ class PostMainController extends BasePostController {
         this._view.sidebarControl.disableForm();
         this._view.sidebarControl.clearMessages();
         const post = e.detail.post;
-        if (e.detail.safety !== undefined && e.detail.safety !== null) {
+        if (e.detail.safety !== undefined) {
             post.safety = e.detail.safety;
         }
-        if (e.detail.flags !== undefined && e.detail.flags !== null) {
+        if (e.detail.flags !== undefined) {
             post.flags = e.detail.flags;
         }
-        if (e.detail.relations !== undefined && e.detail.relations !== null) {
+        if (e.detail.relations !== undefined) {
             post.relations = e.detail.relations;
         }
-        if (e.detail.content !== undefined && e.detail.content !== null) {
+        if (e.detail.content !== undefined) {
             post.newContent = e.detail.content;
         }
-        if (e.detail.thumbnail !== undefined && e.detail.thumbnail !== null) {
+        if (e.detail.thumbnail !== undefined) {
             post.newThumbnail = e.detail.thumbnail;
         }
-        if (e.detail.source !== undefined && e.detail.source !== null) {
+        if (e.detail.source !== undefined) {
             post.source = e.detail.source;
         }
         post.save().then(
diff --git a/client/js/controllers/tag_controller.js b/client/js/controllers/tag_controller.js
index 80e32c78..dfd80bc2 100644
--- a/client/js/controllers/tag_controller.js
+++ b/client/js/controllers/tag_controller.js
@@ -95,13 +95,13 @@ class TagController {
     _evtUpdate(e) {
         this._view.clearMessages();
         this._view.disableForm();
-        if (e.detail.names !== undefined && e.detail.names !== null) {
+        if (e.detail.names !== undefined) {
             e.detail.tag.names = e.detail.names;
         }
-        if (e.detail.category !== undefined && e.detail.category !== null) {
+        if (e.detail.category !== undefined) {
             e.detail.tag.category = e.detail.category;
         }
-        if (e.detail.description !== undefined && e.detail.description !== null) {
+        if (e.detail.description !== undefined) {
             e.detail.tag.description = e.detail.description;
         }
         e.detail.tag.save().then(
diff --git a/client/js/controllers/user_controller.js b/client/js/controllers/user_controller.js
index 8cf46584..068d329e 100644
--- a/client/js/controllers/user_controller.js
+++ b/client/js/controllers/user_controller.js
@@ -175,21 +175,21 @@ class UserController {
         const isLoggedIn = api.isLoggedIn(e.detail.user);
         const infix = isLoggedIn ? "self" : "any";
 
-        if (e.detail.name !== undefined && e.detail.name !== null) {
+        if (e.detail.name !== undefined) {
             e.detail.user.name = e.detail.name;
         }
-        if (e.detail.email !== undefined && e.detail.email !== null) {
+        if (e.detail.email !== undefined) {
             e.detail.user.email = e.detail.email;
         }
-        if (e.detail.rank !== undefined && e.detail.rank !== null) {
+        if (e.detail.rank !== undefined) {
             e.detail.user.rank = e.detail.rank;
         }
 
-        if (e.detail.password !== undefined && e.detail.password !== null) {
+        if (e.detail.password !== undefined) {
             e.detail.user.password = e.detail.password;
         }
 
-        if (e.detail.avatarStyle !== undefined && e.detail.avatarStyle !== null) {
+        if (e.detail.avatarStyle !== undefined) {
             e.detail.user.avatarStyle = e.detail.avatarStyle;
             if (e.detail.avatarContent) {
                 e.detail.user.avatarContent = e.detail.avatarContent;
@@ -302,7 +302,7 @@ class UserController {
         this._view.clearMessages();
         this._view.disableForm();
 
-        if (e.detail.note !== undefined && e.detail.note !== null) {
+        if (e.detail.note !== undefined) {
             e.detail.userToken.note = e.detail.note;
         }
 
diff --git a/client/js/controllers/user_registration_controller.js b/client/js/controllers/user_registration_controller.js
index 89cfd8cd..8b44a2b7 100644
--- a/client/js/controllers/user_registration_controller.js
+++ b/client/js/controllers/user_registration_controller.js
@@ -29,6 +29,7 @@ class UserRegistrationController {
         user.name = e.detail.name;
         user.email = e.detail.email;
         user.password = e.detail.password;
+        user.code = e.detail.code;
         const isLoggedIn = api.isLoggedIn();
         user.save()
             .then(() => {
diff --git a/client/js/controls/metric_header_control.js b/client/js/controls/metric_header_control.js
new file mode 100644
index 00000000..6a70b5ba
--- /dev/null
+++ b/client/js/controls/metric_header_control.js
@@ -0,0 +1,85 @@
+'use strict';
+
+const events = require('../events.js');
+const misc = require('../util/misc.js');
+const views = require('../util/views.js');
+const MetricList = require('../models/metric_list.js');
+
+const mainTemplate = views.getTemplate('metric-header');
+const metricItemTemplate = views.getTemplate('metric-header-item');
+
+class MetricHeaderControl extends events.EventTarget {
+    constructor(hostNode, ctx) {
+        super();
+        this._ctx = ctx;
+        this._hostNode = hostNode;
+        this._selectedMetrics = new MetricList();
+
+        this._headerNode = mainTemplate(ctx);
+        this._metricListNode = this._headerNode.querySelector('ul.metric-list');
+
+        this._hostNode.insertBefore(
+            this._headerNode, this._hostNode.nextSibling);
+
+        MetricList.loadAll().then(response => {
+            this._ctx.allMetrics = response.results;
+            this._addSelectedMetrics(ctx.parameters.metrics);
+            this._installMetrics(response.results);
+            this._refreshStartSortingButton();
+        });
+    }
+
+    _addSelectedMetrics(metricsStr) {
+        let selectedNames = (metricsStr || '').split(' ');
+        for (let metric of [...this._ctx.allMetrics]) {
+            if (selectedNames.includes(metric.tag.names[0])) {
+                this._selectedMetrics.add(metric);
+            }
+        }
+    }
+
+    _installMetrics(metrics) {
+        for (let metric of metrics) {
+            const node = metricItemTemplate(Object.assign({},
+                {
+                    metric: metric,
+                    selected: this._selectedMetrics.includes(metric),
+                },
+                this._ctx));
+            node.addEventListener('click', e =>
+                this._evtMetricClicked(e, node, metric));
+            this._metricListNode.appendChild(node);
+        }
+    }
+
+    _evtMetricClicked(e, node, metric) {
+        e.preventDefault();
+        node.classList.toggle('selected');
+        node.querySelector('a').classList.toggle('selected');
+        if (this._selectedMetrics.includes(metric)) {
+            this._selectedMetrics.remove(metric);
+        } else {
+            this._selectedMetrics.add(metric);
+        }
+        this._ctx.parameters = Object.assign({},
+            this._ctx.parameters, {
+            metrics: this._selectedMetrics
+                .map(m => m.tag.names[0]).join(' '),
+        });
+        this._refreshStartSortingButton();
+        this.dispatchEvent(new CustomEvent('submit'));
+    }
+
+    _refreshStartSortingButton() {
+        let btn = this._hostNode.querySelector('a.sorting');
+        btn.hidden = !this._selectedMetrics.length;
+        btn.setAttribute('href', views.getMetricSorterUrl('random', this._ctx.parameters));
+    }
+
+    refreshQuery(query) {
+        this._ctx.parameters.query = query;
+        this._refreshStartSortingButton();
+    }
+}
+
+module.exports = MetricHeaderControl;
diff --git a/client/js/controls/post_content_control.js b/client/js/controls/post_content_control.js
index 8cbd5d89..55daca76 100644
--- a/client/js/controls/post_content_control.js
+++ b/client/js/controls/post_content_control.js
@@ -103,30 +103,6 @@ class PostContentControl {
     }
 
     _refreshSize() {
-        if (window.innerWidth <= 800) {
-            const buttons = document.querySelector(".sidebar > .buttons");
-            if (buttons) {
-                const content = document.querySelector(".content");
-                content.insertBefore(buttons, content.querySelector(".post-container + *"));
-
-                const afterControls = document.querySelector(".content > .after-mobile-controls");
-                if (afterControls) {
-                    afterControls.parentElement.parentElement.appendChild(afterControls);
-                }
-            }
-        } else {
-            const buttons = document.querySelector(".content > .buttons");
-            if (buttons) {
-                const sidebar = document.querySelector(".sidebar");
-                sidebar.insertBefore(buttons, sidebar.firstElementChild);
-            }
-
-            const afterControls = document.querySelector(".content + .after-mobile-controls");
-            if (afterControls) {
-                document.querySelector(".content").appendChild(afterControls);
-            }
-        }
-
         this._currentFitFunction();
     }
 
diff --git a/client/js/controls/post_edit_sidebar_control.js b/client/js/controls/post_edit_sidebar_control.js
index 3b1c16e7..eabb98ae 100644
--- a/client/js/controls/post_edit_sidebar_control.js
+++ b/client/js/controls/post_edit_sidebar_control.js
@@ -427,7 +427,7 @@ class PostEditSidebarControl extends events.EventTarget {
                         : undefined,
 
                     thumbnail:
-                        this._newPostThumbnail !== undefined && this._newPostThumbnail !== null
+                        this._newPostThumbnail !== undefined
                             ? this._newPostThumbnail
                             : undefined,
 
diff --git a/client/js/controls/post_metric_input_control.js b/client/js/controls/post_metric_input_control.js
new file mode 100644
index 00000000..45b6b245
--- /dev/null
+++ b/client/js/controls/post_metric_input_control.js
@@ -0,0 +1,164 @@
+'use strict';
+
+const uri = require('../util/uri.js');
+const PostMetric = require('../models/post_metric.js');
+const PostMetricRange = require('../models/post_metric_range.js');
+const events = require('../events.js');
+const views = require('../util/views.js');
+
+const mainTemplate = views.getTemplate('post-metric-input');
+const metricNodeTemplate = views.getTemplate('compact-metric-list-item');
+const postMetricNodeTemplate = views.getTemplate('compact-post-metric-list-item');
+const postMetricRangeNodeTemplate = views.getTemplate('compact-post-metric-range-list-item');
+
+class PostMetricInputControl extends events.EventTarget {
+    constructor(hostNode, ctx) {
+        super();
+        this._ctx = ctx;
+        this._post = ctx.post;
+        this._hostNode = hostNode;
+
+        // dom
+        const editAreaNode = mainTemplate({
+            tags: this._post.tags,
+            postMetrics: this._post.metrics,
+        });
+        this._editAreaNode = editAreaNode;
+        this._metricListNode = editAreaNode.querySelector('ul.compact-unset-metrics');
+        this._separatorNode = editAreaNode.querySelector('hr.separator');
+        this._postMetricListNode = editAreaNode.querySelector('ul.compact-post-metrics');
+
+        // show
+        this._hostNode.style.display = 'none';
+        this._hostNode.parentNode.insertBefore(
+            this._editAreaNode, hostNode.nextSibling);
+
+        // add existing metrics and post metrics:
+        this.refreshContent();
+    }
+
+    refreshContent() {
+        this._metricListNode.innerHTML = '';
+        for (let tag of this._post.tags.filterMetrics()) {
+            const metricNode = this._createMetricNode(tag);
+            this._metricListNode.appendChild(metricNode);
+        }
+        this._postMetricListNode.innerHTML = '';
+        for (let pm of this._post.metrics) {
+            const postMetricNode = this._createPostMetricNode(pm);
+            this._postMetricListNode.appendChild(postMetricNode);
+        }
+        for (let pmr of this._post.metricRanges) {
+            const postMetricRangeNode = this._createPostMetricRangeNode(pmr);
+            this._postMetricListNode.appendChild(postMetricRangeNode);
+        }
+        this._separatorNode.style.display =
+            this._postMetricListNode.innerHTML ? 'block' : 'none';
+    }
+
+    _createMetricNode(tag) {
+        const node = metricNodeTemplate({
+            editMode: true,
+            tag: tag,
+            post: this._post,
+            query: this._ctx.parameters.query,
+        });
+        const createExactNode = node.querySelector('a.create-exact');
+        if (this._post.metrics.hasTagName(tag.names[0])) {
+            createExactNode.style.display = 'none';
+        } else {
+            createExactNode.addEventListener('click', e => {
+                e.preventDefault();
+                this.createPostMetric(tag);
+            });
+        }
+        const createRangeNode = node.querySelector('a.create-range');
+        if (this._post.metricRanges.hasTagName(tag.names[0])) {
+            createRangeNode.style.display = 'none';
+        } else {
+            createRangeNode.addEventListener('click', e => {
+                e.preventDefault();
+                this.createPostMetricRange(tag);
+            });
+        }
+        const sortNode = node.querySelector('a.sort');
+        if (this._post.metrics.hasTagName(tag.names[0])) {
+            sortNode.style.display = 'none';
+        }
+        return node;
+    }
+
+    _createPostMetricNode(pm) {
+        const tag = this._post.tags.findByName(pm.tagName);
+        const node = postMetricNodeTemplate({
+            editMode: true,
+            postMetric: pm,
+            tag: tag,
+        });
+        node.querySelector('input[name=value]').addEventListener('change', e => {
+            pm.value = e.target.value;
+            this.dispatchEvent(new CustomEvent('change'));
+        });
+        node.querySelector('.remove-metric').addEventListener('click', e => {
+            e.preventDefault();
+            this.deletePostMetric(pm);
+        });
+        return node;
+    }
+
+    _createPostMetricRangeNode(pmr) {
+        const tag = this._post.tags.findByName(pmr.tagName);
+        const node = postMetricRangeNodeTemplate({
+            editMode: true,
+            postMetricRange: pmr,
+            tag: tag,
+        });
+        node.querySelector('input[name=low]').addEventListener('change', e => {
+            pmr.low = e.target.value;
+            this.dispatchEvent(new CustomEvent('change'));
+        });
+        node.querySelector('input[name=high]').addEventListener('change', e => {
+            pmr.high = e.target.value;
+            this.dispatchEvent(new CustomEvent('change'));
+        });
+        node.querySelector('.remove-metric').addEventListener('click', e => {
+            e.preventDefault();
+            this.deletePostMetricRange(pmr);
+        });
+        return node;
+    }
+
+    createPostMetric(tag) {
+        let postMetricRange = this._post.metricRanges.findByTagName(tag.names[0]);
+        if (postMetricRange) {
+            this._post.metricRanges.remove(postMetricRange);
+        }
+        this._post.metrics.add(PostMetric.create(this._post.id, tag));
+        this.refreshContent();
+        this.dispatchEvent(new CustomEvent('change'));
+    }
+
+    createPostMetricRange(tag) {
+        let postMetric = this._post.metrics.findByTagName(tag.names[0]);
+        if (postMetric) {
+            this._post.metrics.remove(postMetric);
+        }
+        this._post.metricRanges.add(PostMetricRange.create(this._post.id, tag));
+        this.refreshContent();
+        this.dispatchEvent(new CustomEvent('change'));
+    }
+
+    deletePostMetric(pm) {
+        this._post.metrics.remove(pm);
+        this.refreshContent();
+        this.dispatchEvent(new CustomEvent('change'));
+    }
+
+    deletePostMetricRange(pmr) {
+        this._post.metricRanges.remove(pmr);
+        this.refreshContent();
+        this.dispatchEvent(new CustomEvent('change'));
+    }
+}
+
+module.exports = PostMetricInputControl;
diff --git a/client/js/controls/post_metric_list_control.js b/client/js/controls/post_metric_list_control.js
new file mode 100644
index 00000000..b179b121
--- /dev/null
+++ b/client/js/controls/post_metric_list_control.js
@@ -0,0 +1,51 @@
+'use strict';
+
+const events = require('../events.js');
+const views = require('../util/views.js');
+
+const postMetricNodeTemplate = views.getTemplate('compact-post-metric-list-item');
+const postMetricRangeNodeTemplate = views.getTemplate('compact-post-metric-range-list-item');
+
+class PostMetricListControl extends events.EventTarget {
+    constructor(listNode, post) {
+        super();
+        this._post = post;
+        this._listNode = listNode;
+
+        this._refreshContent();
+    }
+
+    _refreshContent() {
+        this._listNode.innerHTML = '';
+        for (let pm of this._post.metrics) {
+            const postMetricNode = this._createPostMetricNode(pm);
+            this._listNode.appendChild(postMetricNode);
+        }
+        for (let pmr of this._post.metricRanges) {
+            const postMetricRangeNode = this._createPostMetricRangeNode(pmr);
+            this._listNode.appendChild(postMetricRangeNode);
+        }
+    }
+
+    _createPostMetricNode(pm) {
+        const tag = this._post.tags.findByName(pm.tagName);
+        const node = postMetricNodeTemplate({
+            editMode: false,
+            postMetric: pm,
+            tag: tag,
+        });
+        return node;
+    }
+
+    _createPostMetricRangeNode(pmr) {
+        const tag = this._post.tags.findByName(pmr.tagName);
+        const node = postMetricRangeNodeTemplate({
+            editMode: false,
+            postMetricRange: pmr,
+            tag: tag,
+        });
+        return node;
+    }
+}
+
+module.exports = PostMetricListControl;
diff --git a/client/js/models/metric.js b/client/js/models/metric.js
new file mode 100644
index 00000000..bb9cf84a
--- /dev/null
+++ b/client/js/models/metric.js
@@ -0,0 +1,88 @@
+'use strict';
+
+const api = require('../api.js');
+const uri = require('../util/uri.js');
+const events = require('../events.js');
+const misc = require('../util/misc.js');
+const Tag = require('./tag.js');
+
+class Metric extends events.EventTarget {
+    constructor() {
+        super();
+        this._orig = {};
+
+        this._updateFromResponse({});
+    }
+
+    get version()  { return this._version; }
+    get min()      { return this._min; }
+    get max()      { return this._max; }
+    get tag()      { return this._tag; }
+
+    set min(value) { this._min = value; }
+    set max(value) { this._max = value; }
+
+    static fromResponse(response) {
+        const ret = new Metric();
+        ret._updateFromResponse(response);
+        return ret;
+    }
+
+    static get(name) {
+        //TODO get metric. Or only via tag?
+        return api.get(uri.formatApiLink('metric', name))
+            .then(response => {
+                return Promise.resolve(Metric.fromResponse(response));
+            });
+    }
+
+    save() {
+        const detail = {version: this._version};
+
+        if (this._min !== this._orig._min) {
+            detail.min = this._min;
+        }
+        if (this._max !== this._orig._max) {
+            detail.max = this._max;
+        }
+
+        return api.post(uri.formatApiLink('metrics'), detail)
+            .then(response => {
+                this._updateFromResponse(response);
+                this.dispatchEvent(new CustomEvent('change', {
+                    detail: {
+                        metric: this,
+                    },
+                }));
+                return Promise.resolve();
+            });
+    }
+
+    delete() {
+        return api.delete(
+            uri.formatApiLink('metric', this._orig),
+            {version: this._version})
+            .then(response => {
+                this.dispatchEvent(new CustomEvent('delete', {
+                    detail: {
+                        metric: this,
+                    },
+                }));
+                return Promise.resolve();
+            });
+    }
+
+    _updateFromResponse(response) {
+        const map = {
+            _version:      response.version,
+            _min:          response.min,
+            _max:          response.max,
+            _tag:          Tag.fromResponse(response.tag || {}),
+        };
+
+        Object.assign(this, map);
+        Object.assign(this._orig, map);
+    }
+}
+
+module.exports = Metric;
diff --git a/client/js/models/metric_list.js b/client/js/models/metric_list.js
new file mode 100644
index 00000000..83aba110
--- /dev/null
+++ b/client/js/models/metric_list.js
@@ -0,0 +1,24 @@
+'use strict';
+
+const api = require('../api.js');
+const uri = require('../util/uri.js');
+const AbstractList = require('./abstract_list.js');
+const Metric = require('./metric.js');
+
+class MetricList extends AbstractList {
+    static loadAll() {
+        return api.get(
+            uri.formatApiLink('metrics'))
+            .then(response => {
+                return Promise.resolve(Object.assign(
+                    {},
+                    response,
+                    {results: MetricList.fromResponse(response.results)}));
+            });
+    }
+}
+
+MetricList._itemClass = Metric;
+MetricList._itemName = 'metric';
+
+module.exports = MetricList;
diff --git a/client/js/models/post.js b/client/js/models/post.js
index 01f81bf1..2fb3d34c 100644
--- a/client/js/models/post.js
+++ b/client/js/models/post.js
@@ -271,7 +271,7 @@ class Post extends events.EventTarget {
         if (this._newContent) {
             files.content = this._newContent;
         }
-        if (this._newThumbnail !== undefined && this._newThumbnail !== null) {
+        if (this._newThumbnail !== undefined) {
             files.thumbnail = this._newThumbnail;
         }
         if (this._source !== this._orig._source) {
diff --git a/client/js/models/post_list.js b/client/js/models/post_list.js
index 8c2c9d4e..6838a5cb 100644
--- a/client/js/models/post_list.js
+++ b/client/js/models/post_list.js
@@ -16,7 +16,7 @@ class PostList extends AbstractList {
         );
     }
 
-    static search(text, offset, limit, fields) {
+    static search(text, offset, limit, fields, cachenumber) {
         return api
             .get(
                 uri.formatApiLink("posts", {
@@ -24,6 +24,7 @@ class PostList extends AbstractList {
                     offset: offset,
                     limit: limit,
                     fields: fields.join(","),
+                    cachenumber: cachenumber,
                 })
             )
             .then((response) => {
diff --git a/client/js/models/post_metric.js b/client/js/models/post_metric.js
new file mode 100644
index 00000000..dd06957a
--- /dev/null
+++ b/client/js/models/post_metric.js
@@ -0,0 +1,39 @@
+'use strict';
+
+const events = require('../events.js');
+
+class PostMetric extends events.EventTarget {
+    constructor() {
+        super();
+        this._updateFromResponse({});
+    }
+
+    static create(postId, tag) {
+        const metric = new PostMetric();
+        metric._postId = postId;
+        metric._tagName = tag.names[0];
+        metric._value = tag.metric.min;
+        return metric;
+    }
+
+    static fromResponse(response) {
+        const metric = new PostMetric();
+        metric._updateFromResponse(response);
+        return metric;
+    }
+
+    get tagName()    { return this._tagName; }
+    get postId()     { return this._postId; }
+    get value()      { return this._value; }
+
+    set value(value) { this._value = value; }
+
+    _updateFromResponse(response) {
+        this._version      = response.version;
+        this._postId       = response.post_id;
+        this._tagName      = response.tag_name;
+        this._value        = response.value;
+    }
+}
+
+module.exports = PostMetric;
\ No newline at end of file
diff --git a/client/js/models/post_metric_list.js b/client/js/models/post_metric_list.js
new file mode 100644
index 00000000..5e2c8386
--- /dev/null
+++ b/client/js/models/post_metric_list.js
@@ -0,0 +1,24 @@
+'use strict';
+
+const AbstractList = require('./abstract_list.js');
+const PostMetric = require('./post_metric.js');
+
+class PostMetricList extends AbstractList {
+    findByTagName(testName) {
+        for (let postMetric of this._list) {
+            if (postMetric.tagName.toLowerCase() === testName.toLowerCase()) {
+                return postMetric;
+            }
+        }
+        return null;
+    }
+
+    hasTagName(testName) {
+        return !!this.findByTagName(testName);
+    }
+}
+
+PostMetricList._itemClass = PostMetric;
+PostMetricList._itemName = 'postMetric';
+
+module.exports = PostMetricList;
diff --git a/client/js/models/post_metric_range.js b/client/js/models/post_metric_range.js
new file mode 100644
index 00000000..ab7bddba
--- /dev/null
+++ b/client/js/models/post_metric_range.js
@@ -0,0 +1,43 @@
+'use strict';
+
+const events = require('../events.js');
+
+class PostMetricRange extends events.EventTarget {
+    constructor() {
+        super();
+        this._updateFromResponse({});
+    }
+
+    static create(postId, tag) {
+        const metric = new PostMetricRange();
+        metric._postId = postId;
+        metric._tagName = tag.names[0];
+        metric._low = tag.metric.min;
+        metric._high = tag.metric.max;
+        return metric;
+    }
+
+    static fromResponse(response) {
+        const metric = new PostMetricRange();
+        metric._updateFromResponse(response);
+        return metric;
+    }
+
+    get tagName()    { return this._tagName; }
+    get postId()     { return this._postId; }
+    get low()        { return this._low; }
+    get high()       { return this._high; }
+
+    set low(value)   { this._low = value; }
+    set high(value)  { this._high = value; }
+
+    _updateFromResponse(response) {
+        this._version  = response.version;
+        this._postId   = response.post_id;
+        this._tagName  = response.tag_name;
+        this._low      = response.low;
+        this._high     = response.high;
+    }
+}
+
+module.exports = PostMetricRange;
\ No newline at end of file
diff --git a/client/js/models/post_metric_range_list.js b/client/js/models/post_metric_range_list.js
new file mode 100644
index 00000000..68e701b6
--- /dev/null
+++ b/client/js/models/post_metric_range_list.js
@@ -0,0 +1,24 @@
+'use strict';
+
+const AbstractList = require('./abstract_list.js');
+const PostMetricRange = require('./post_metric_range.js');
+
+class PostMetricRangeList extends AbstractList {
+    findByTagName(testName) {
+        for (let pmr of this._list) {
+            if (pmr.tagName.toLowerCase() === testName.toLowerCase()) {
+                return pmr;
+            }
+        }
+        return null;
+    }
+
+    hasTagName(testName) {
+        return !!this.findByTagName(testName);
+    }
+}
+
+PostMetricRangeList._itemClass = PostMetricRange;
+PostMetricRangeList._itemName = 'postMetricRange';
+
+module.exports = PostMetricRangeList;
diff --git a/client/js/util/touch.js b/client/js/util/touch.js
index 64bd00ac..85b66d84 100644
--- a/client/js/util/touch.js
+++ b/client/js/util/touch.js
@@ -12,6 +12,7 @@ function handleTouchStart(handler, evt) {
     const touchEvent = evt.touches[0];
     handler._xStart = touchEvent.clientX;
     handler._yStart = touchEvent.clientY;
+    handler._startScrollY = window.scrollY;
 }
 
 function handleTouchMove(handler, evt) {
@@ -35,22 +36,22 @@ function handleTouchMove(handler, evt) {
     }
 }
 
-function handleTouchEnd(handler) {
+function handleTouchEnd(handler, evt) {
+    evt.startScrollY = handler._startScrollY;
     switch (handler._direction) {
         case direction.NONE:
             return;
         case direction.LEFT:
-            handler._swipeLeftTask();
+            handler._swipeLeftTask(evt);
             break;
         case direction.RIGHT:
-            handler._swipeRightTask();
+            handler._swipeRightTask(evt);
             break;
         case direction.DOWN:
-            handler._swipeDownTask();
+            handler._swipeDownTask(evt);
             break;
         case direction.UP:
-            handler._swipeUpTask();
-        // no default
+            handler._swipeUpTask(evt);
     }
 
     handler._xStart = null;
@@ -76,15 +77,15 @@ class Touch {
         this._yStart = null;
         this._direction = direction.NONE;
 
-        this._target.addEventListener("touchstart", (evt) => {
-            handleTouchStart(this, evt);
-        });
-        this._target.addEventListener("touchmove", (evt) => {
-            handleTouchMove(this, evt);
-        });
-        this._target.addEventListener("touchend", () => {
-            handleTouchEnd(this);
-        });
+        this._target.addEventListener('touchstart', (evt) => 
+            { handleTouchStart(this, evt); }
+        );
+        this._target.addEventListener('touchmove', (evt) =>
+            { handleTouchMove(this, evt); }
+        );
+        this._target.addEventListener('touchend', (evt) =>
+            { handleTouchEnd(this, evt); }
+        );
     }
 }
 
diff --git a/client/js/util/views.js b/client/js/util/views.js
index f6280a1c..878c92fb 100644
--- a/client/js/util/views.js
+++ b/client/js/util/views.js
@@ -136,6 +136,11 @@ function makePasswordInput(options) {
     return makeInput(options);
 }
 
+function makeCodeInput(options) {
+    options.type = "code";
+    return makeInput(options);
+}
+
 function makeEmailInput(options) {
     options.type = "email";
     return makeInput(options);
@@ -209,13 +214,13 @@ function makePostLink(id, includeHash) {
 }
 
 function makeTagLink(name, includeHash, includeCount, tag) {
-    const category = tag && tag.category ? tag.category : "unknown";
+    const category = tag ? tag.category : "unknown";
     let text = misc.getPrettyName(name);
     if (includeHash === true) {
         text = "#" + text;
     }
     if (includeCount === true) {
-        text += " (" + (tag && tag.postCount ? tag.postCount : 0) + ")";
+        text += " (" + (tag ? tag.postCount : 0) + ")";
     }
     return api.hasPrivilege("tags:view")
         ? makeElement(
@@ -234,15 +239,15 @@ function makeTagLink(name, includeHash, includeCount, tag) {
 }
 
 function makePoolLink(id, includeHash, includeCount, pool, name) {
-    const category = pool && pool.category ? pool.category : "unknown";
+    const category = pool ? pool.category : "unknown";
     let text = misc.getPrettyName(
-        name ? name : pool && pool.names ? pool.names[0] : "pool " + id
+        name ? name : pool ? pool.names[0] : "unknown"
     );
     if (includeHash === true) {
         text = "#" + text;
     }
     if (includeCount === true) {
-        text += " (" + (pool && pool.postCount ? pool.postCount : 0) + ")";
+        text += " (" + (pool ? pool.postCount : 0) + ")";
     }
     return api.hasPrivilege("pools:view")
         ? makeElement(
@@ -264,7 +269,7 @@ function makeUserLink(user) {
     let text = makeThumbnail(user ? user.avatarUrl : null);
     text += user && user.name ? misc.escapeHtml(user.name) : "Anonymous";
     const link =
-        user && user.name && api.hasPrivilege("users:view")
+        user && api.hasPrivilege("users:view")
             ? makeElement(
                   "a",
                   { href: uri.formatClientLink("user", user.name) },
@@ -444,6 +449,7 @@ function getTemplate(templatePath) {
             makeTextarea: makeTextarea,
             makeTextInput: makeTextInput,
             makePasswordInput: makePasswordInput,
+            makeCodeInput: makeCodeInput,
             makeEmailInput: makeEmailInput,
             makeColorInput: makeColorInput,
             makeDateInput: makeDateInput,
diff --git a/client/js/views/metric_sorter_view.js b/client/js/views/metric_sorter_view.js
new file mode 100644
index 00000000..763a1de8
--- /dev/null
+++ b/client/js/views/metric_sorter_view.js
@@ -0,0 +1,138 @@
+'use strict';
+
+const events = require('../events.js');
+const views = require('../util/views.js');
+const iosCorrectedInnerHeight = require('ios-inner-height');
+const PostContentControl = require('../controls/post_content_control.js');
+
+const template = views.getTemplate('metric-sorter');
+const sideTemplate = views.getTemplate('metric-sorter-side');
+
+//TODO: find a way to export these constants once
+const LEFT = 'left';
+const RIGHT = 'right';
+
+class MetricSorterView extends events.EventTarget {
+    constructor(ctx) {
+        super();
+
+        this._ctx = ctx;
+        this._hostNode = document.getElementById('content-holder');
+        views.replaceContent(this._hostNode, template(ctx));
+        this._formNode.addEventListener('submit', e => this._evtFormSubmit(e));
+        this._skipButtonNode.addEventListener('click', e => this._evtSkipClick(e));
+        this._compareLessBtnNode.addEventListener('click', e => this._evtCompareClick(e));
+        this._compareGreaterBtnNode.addEventListener('click', e => this._evtCompareClick(e));
+        this._refreshCompareButton();
+    }
+
+    installLeftPost(post) {
+        this._leftPostControl = this._installPostControl(post, this._leftSideNode);
+    }
+
+    installRightPost(post) {
+        this._rightPostControl = this._installPostControl(post, this._rightSideNode);
+    }
+
+    _installPostControl(post, sideNode) {
+        views.replaceContent(
+            sideNode,
+            sideTemplate(Object.assign({}, this._ctx, {
+                post: post,
+            })));
+        let containerNode = this._getSidePostContainerNode(sideNode);
+        return new PostContentControl(
+            containerNode,
+            post,
+            () => {
+                // TODO: come up with a more reliable resizing mechanism
+                return window.innerWidth < 1000 ?
+                    [
+                        window.innerWidth,
+                        iosCorrectedInnerHeight() / 2
+                    ] : [
+                        containerNode.getBoundingClientRect().width,
+                        window.innerHeight - containerNode.getBoundingClientRect().top -
+                            this._buttonsNode.getBoundingClientRect().height * 2
+                    ];
+            });
+    }
+
+    clearMessages() {
+        views.clearMessages(this._hostNode);
+    }
+
+    enableForm() {
+        views.enableForm(this._formNode);
+    }
+
+    disableForm() {
+        views.disableForm(this._formNode);
+    }
+
+    showSuccess(message) {
+        views.showSuccess(this._hostNode, message);
+    }
+
+    showError(message) {
+        views.showError(this._hostNode, message);
+    }
+
+    get _formNode() {
+        return this._hostNode.querySelector('form');
+    }
+
+    get _leftSideNode() {
+        return this._hostNode.querySelector('.left-post-container');
+    }
+
+    get _rightSideNode() {
+        return this._hostNode.querySelector('.right-post-container');
+    }
+
+    get _compareGreaterBtnNode() {
+        return this._hostNode.querySelector('.left-gt-right')
+    }
+
+    get _compareLessBtnNode() {
+        return this._hostNode.querySelector('.left-lt-right')
+    }
+
+    get _buttonsNode() {
+        return this._hostNode.querySelector('.buttons');
+    }
+
+    get _skipButtonNode() {
+        return this._hostNode.querySelector('.skip-btn');
+    }
+
+    _getSidePostContainerNode(sideNode) {
+        return sideNode.querySelector('.post-container');
+    }
+
+    _evtSkipClick(e) {
+        e.preventDefault();
+        this.dispatchEvent(new CustomEvent('skip'));
+    }
+
+    _evtFormSubmit(e) {
+        e.preventDefault();
+        this.dispatchEvent(new CustomEvent('submit', {
+            detail: {
+                greaterPost: this._ctx.greaterPost,
+            }}));
+    }
+
+    _evtCompareClick(e) {
+        e.preventDefault();
+        this._ctx.greaterPost = this._ctx.greaterPost === LEFT ? RIGHT : LEFT;
+        this._refreshCompareButton();
+    }
+
+    _refreshCompareButton() {
+        this._compareGreaterBtnNode.hidden = this._ctx.greaterPost === RIGHT;
+        this._compareLessBtnNode.hidden = this._ctx.greaterPost === LEFT;
+    }
+}
+
+module.exports = MetricSorterView;
diff --git a/client/js/views/post_main_view.js b/client/js/views/post_main_view.js
index 5ef7f61e..f9713912 100644
--- a/client/js/views/post_main_view.js
+++ b/client/js/views/post_main_view.js
@@ -86,6 +86,12 @@ class PostMainView {
             }
         };
 
+        const showRandomImage = () => {
+            if (ctx.randomPostId) {
+                router.show(ctx.getPostUrl(ctx.randomPostId, ctx.parameters));
+            }
+        };
+
         keyboard.bind("e", () => {
             if (ctx.editMode) {
                 router.show(uri.formatClientLink("post", ctx.post.id));
@@ -95,6 +101,7 @@ class PostMainView {
         });
         keyboard.bind(["a", "left"], showPreviousImage);
         keyboard.bind(["d", "right"], showNextImage);
+	    keyboard.bind("r", showRandomImage);
         keyboard.bind("del", (e) => {
             if (ctx.editMode) {
                 this.sidebarControl._evtDeleteClick(e);
@@ -105,15 +112,21 @@ class PostMainView {
             postContainerNode,
             () => {
                 if (!ctx.editMode) {
-                    showPreviousImage();
+                    showNextImage()
                 }
             },
             () => {
                 if (!ctx.editMode) {
-                    showNextImage();
+                    showPreviousImage()
+                }
+            },
+            () => {},
+            (e) => {
+                if (!ctx.editMode && e.startScrollY === 0) {
+                    showRandomImage()
                 }
             }
-        );
+        )
     }
 
     _installSidebar(ctx) {
diff --git a/client/js/views/posts_header_view.js b/client/js/views/posts_header_view.js
index 38a4aa98..4f04eb42 100644
--- a/client/js/views/posts_header_view.js
+++ b/client/js/views/posts_header_view.js
@@ -197,8 +197,11 @@ class PostsHeaderView extends events.EventTarget {
                 this._evtSafetyButtonClick(e)
             );
         }
-        this._formNode.addEventListener("submit", (e) =>
-            this._evtFormSubmit(e)
+
+        this._formNode.addEventListener('submit', e =>
+            this._evtFormSubmit(e));
+        this._randomizeButtonNode.addEventListener('click', e =>
+            this._evtRandomizeButtonClick(e)
         );
 
         this._bulkEditors = [];
@@ -256,6 +259,10 @@ class PostsHeaderView extends events.EventTarget {
         return this._hostNode.querySelector("form [name=search-text]");
     }
 
+    get _randomizeButtonNode() {
+        return this._hostNode.querySelector('#randomize-button');
+    }
+    
     get _bulkEditTagsNode() {
         return this._hostNode.querySelector(".bulk-edit-tags");
     }
@@ -314,9 +321,21 @@ class PostsHeaderView extends events.EventTarget {
         this._navigate();
     }
 
+    _evtRandomizeButtonClick(e) {
+        e.preventDefault();
+        if (!this._queryInputNode.value.includes('sort:random')) {
+            this._queryInputNode.value += ' sort:random';
+        }
+        this._ctx.parameters.cachenumber = Math.round(Math.random() * 1000);
+        this._navigate();
+    }
+
     _navigate() {
         this._autoCompleteControl.hide();
-        let parameters = { query: this._queryInputNode.value };
+        let parameters = {
+            query: this._queryInputNode.value,
+            cachenumber: this._ctx.parameters.cachenumber,
+        };
 
         // convert falsy values to an empty string "" so that we can correctly compare with the current query
         const prevQuery = this._ctx.parameters.query
diff --git a/client/js/views/registration_view.js b/client/js/views/registration_view.js
index 0a08de23..31642227 100644
--- a/client/js/views/registration_view.js
+++ b/client/js/views/registration_view.js
@@ -15,6 +15,7 @@ class RegistrationView extends events.EventTarget {
             template({
                 userNamePattern: api.getUserNameRegex(),
                 passwordPattern: api.getPasswordRegex(),
+                codePattern: api.getCodeRegex(),
             })
         );
         views.syncScrollPosition();
@@ -45,6 +46,7 @@ class RegistrationView extends events.EventTarget {
                 detail: {
                     name: this._userNameFieldNode.value,
                     password: this._passwordFieldNode.value,
+                    code: this._codeFieldNode.value,
                     email: this._emailFieldNode.value,
                 },
             })
@@ -63,6 +65,10 @@ class RegistrationView extends events.EventTarget {
         return this._formNode.querySelector("[name=password]");
     }
 
+    get _codeFieldNode() {
+        return this._formNode.querySelector("[name=code]");
+    }
+
     get _emailFieldNode() {
         return this._formNode.querySelector("[name=email]");
     }
diff --git a/client/js/views/tag_metric_view.js b/client/js/views/tag_metric_view.js
new file mode 100644
index 00000000..d7cb67f5
--- /dev/null
+++ b/client/js/views/tag_metric_view.js
@@ -0,0 +1,97 @@
+'use strict';
+
+const events = require('../events.js');
+const api = require('../api.js');
+const views = require('../util/views.js');
+const Metric = require('../models/metric.js');
+
+const template = views.getTemplate('tag-metric');
+
+class TagMetricView extends events.EventTarget {
+    constructor(ctx) {
+        super();
+
+        this._tag = ctx.tag;
+        this._hostNode = ctx.hostNode;
+
+        if (ctx.tag.metric) {
+            ctx.metricMin = ctx.tag.metric.min;
+            ctx.metricMax = ctx.tag.metric.max;
+        } else {
+            // default new values
+            ctx.metricMin = 0;
+            ctx.metricMax = 10;
+        }
+
+        views.replaceContent(this._hostNode, template(ctx));
+
+        this._formNode.addEventListener('submit', e => this._evtSubmit(e));
+        if (this._deleteButtonNode) {
+            this._deleteButtonNode.addEventListener('click', e => this._evtDelete(e));
+        }
+    }
+
+    _evtSubmit(e) {
+        e.preventDefault();
+        this.dispatchEvent(new CustomEvent('submit', {
+            detail: {
+                tag: this._tag,
+                metricMin: this._minFieldNode.value,
+                metricMax: this._maxFieldNode.value,
+            },
+        }));
+    }
+
+    _evtDelete(e) {
+        e.preventDefault();
+        if (!this._deleteConfirmationNode.checked) {
+            this.showError('Please confirm deletion.')
+        } else {
+            this.dispatchEvent(new CustomEvent('delete', {
+                detail: {tag: this._tag},
+            }));
+        }
+    }
+
+    clearMessages() {
+        views.clearMessages(this._hostNode);
+    }
+
+    enableForm() {
+        views.enableForm(this._formNode);
+    }
+
+    disableForm() {
+        views.disableForm(this._formNode);
+    }
+
+    showSuccess(message) {
+        views.showSuccess(this._hostNode, message);
+    }
+
+    showError(message) {
+        views.showError(this._hostNode, message);
+    }
+
+    get _formNode() {
+        return this._hostNode.querySelector('form');
+    }
+
+    get _minFieldNode() {
+        return this._formNode.querySelector('input[name=metric-min]');
+    }
+
+    get _maxFieldNode() {
+        return this._formNode.querySelector('input[name=metric-max]');
+    }
+
+    get _deleteConfirmationNode() {
+        return this._formNode.querySelector('input[name=confirm-delete]');
+    }
+
+    get _deleteButtonNode() {
+        return this._formNode.querySelector('input[name=delete]');
+    }
+}
+
+module.exports = TagMetricView;
diff --git a/customdocker2 master.7z b/customdocker2 master.7z
new file mode 100644
index 00000000..d447093e
Binary files /dev/null and b/customdocker2 master.7z differ
diff --git a/customdocker2 stable master v2.7z b/customdocker2 stable master v2.7z
new file mode 100644
index 00000000..f7b5d3ba
Binary files /dev/null and b/customdocker2 stable master v2.7z differ
diff --git a/doc/API.md b/doc/API.md
index 00ee75a9..3d280fd1 100644
--- a/doc/API.md
+++ b/doc/API.md
@@ -37,7 +37,6 @@
         - [Creating post](#creating-post)
         - [Updating post](#updating-post)
         - [Getting post](#getting-post)
-        - [Getting around post](#getting-around-post)
         - [Deleting post](#deleting-post)
         - [Merging posts](#merging-posts)
         - [Rating post](#rating-post)
@@ -54,7 +53,7 @@
         - [Deleting pool category](#deleting-pool-category)
         - [Setting default pool category](#setting-default-pool-category)
     - Pools
-        - [Listing pools](#listing-pools)
+        - [Listing pools](#listing-pool)
         - [Creating pool](#creating-pool)
         - [Updating pool](#updating-pool)
         - [Getting pool](#getting-pool)
@@ -165,9 +164,9 @@ way. The files, however, should be passed as regular fields appended with a
 accepts a file named `content`, the client should pass
 `{"contentUrl":"http://example.com/file.jpg"}` as a part of the JSON message
 body. When creating or updating post content using this method, the server can
-also be configured to employ [yt-dlp](https://github.com/yt-dlp/yt-dlp) to
-download content from popular sites such as youtube, gfycat, etc. Access to
-yt-dlp can be configured with the `'uploads:use_downloader'` permission
+also be configured to employ [youtube-dl](https://github.com/ytdl-org/youtube-dl)
+to download content from popular sites such as youtube, gfycat, etc. Access to
+youtube-dl can be configured with the `'uploads:use_downloader'` permission
 
 Finally, in some cases the user might want to reuse one file between the
 requests to save the bandwidth (for example, reverse search + consecutive
@@ -323,7 +322,7 @@ data.
     {
         "name":  <name>,
         "color": <color>,
-        "order": <order>
+        "order": <order>  // optional
     }
     ```
 
@@ -952,29 +951,6 @@ data.
 
     Retrieves information about an existing post.
 
-## Getting around post
-- **Request**
-
-    `GET /post/<id>/around`
-
-- **Output**
-
-    ```json5
-    {
-        "prev":  <post-resource>,
-        "next":  <post-resource>
-    }
-    ```
-
-- **Errors**
-
-    - the post does not exist
-    - privileges are too low
-
-- **Description**
-
-    Retrieves information about posts that are before or after an existing post.
-
 ## Deleting post
 - **Request**
 
@@ -1389,7 +1365,7 @@ data.
 ## Creating pool
 - **Request**
 
-    `POST /pool`
+    `POST /pools/create`
 
 - **Input**
 
@@ -2491,7 +2467,7 @@ One file together with its metadata posted to the site.
 ## Micro post
 **Description**
 
-A [post resource](#post) stripped down to `id` and `thumbnailUrl` fields.
+A [post resource](#post) stripped down to `name` and `thumbnailUrl` fields.
 
 ## Note
 **Description**
diff --git a/doc/INSTALL.md b/doc/INSTALL.md
index ca0212bf..d978e4a8 100644
--- a/doc/INSTALL.md
+++ b/doc/INSTALL.md
@@ -34,79 +34,33 @@ and Docker Compose (version 1.6.0 or greater) already installed.
     Read the comments to guide you. Note that `.env` should be in the root
     directory of this repository.
 
-4. Pull the containers:
+### Running the Application
 
-    This pulls the latest containers from docker.io:
-    ```console
-    user@host:szuru$ docker-compose pull
-    ```
+Download containers:
+```console
+user@host:szuru$ docker-compose pull
+```
 
-    If you have modified the application's source and would like to manually
-    build it, follow the instructions in [**Building**](#Building) instead,
-    then read here once you're done.
+For first run, it is recommended to start the database separately:
+```console
+user@host:szuru$ docker-compose up -d sql
+```
 
-5. Run it!
+To start all containers:
+```console
+user@host:szuru$ docker-compose up -d
+```
 
-    For first run, it is recommended to start the database separately:
-    ```console
-    user@host:szuru$ docker-compose up -d sql
-    ```
-
-    To start all containers:
-    ```console
-    user@host:szuru$ docker-compose up -d
-    ```
-
-    To view/monitor the application logs:
-    ```console
-    user@host:szuru$ docker-compose logs -f
-    # (CTRL+C to exit)
-    ```
-
-### Building
-
-1. Edit `docker-compose.yml` to tell Docker to build instead of pull containers:
-
-    ```diff yaml
-    ...
-    server:
-    - image: szurubooru/server:latest
-    + build: server
-    ...
-    client:
-    - image: szurubooru/client:latest
-    + build: client
-    ...
-    ```
-
-    You can choose to build either one from source.
-
-2. Build the containers:
-
-    ```console
-    user@host:szuru$ docker-compose build
-    ```
-
-    That will attempt to build both containers, but you can specify `client`
-    or `server` to make it build only one.
-
-    If `docker-compose build` spits out:
-
-    ```
-    ERROR: Service 'server' failed to build: failed to parse platform : "" is an invalid component of "": platform specifier component must match "^[A-Za-z0-9_-]+$": invalid argument
-    ```
-
-    ...you will need to export Docker BuildKit flags:
-
-    ```console
-    user@host:szuru$ export DOCKER_BUILDKIT=1; export COMPOSE_DOCKER_CLI_BUILD=1
-    ```
-
-    ...and run `docker-compose build` again.
-
-*Note: If your changes are not taking effect in your builds, consider building
-with `--no-cache`.*
+To view/monitor the application logs:
+```console
+user@host:szuru$ docker-compose logs -f
+# (CTRL+C to exit)
+```
 
+To stop all containers:
+```console
+user@host:szuru$ docker-compose down
+```
 
 ### Additional Features
 
diff --git a/doc/example.env b/doc/example.env
index 303a25e6..59e1e859 100644
--- a/doc/example.env
+++ b/doc/example.env
@@ -10,12 +10,6 @@ BUILD_INFO=latest
 # otherwise the port specified here will be publicly accessible
 PORT=8080
 
-# How many waitress threads to start
-# 4 is the default amount of threads. If you experience performance
-# degradation with a large number of posts, increasing this may
-# improve performance, since waitress is most likely clogging up with Tasks.
-THREADS=4
-
 # URL base to run szurubooru under
 # See "Additional Features" section in INSTALL.md
 BASE_URL=/
diff --git a/docker-compose.yml b/docker-compose.yml
index 38e08b97..b4f689c4 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -2,32 +2,39 @@
 ##
 ## Use this as a template to set up docker-compose, or as guide to set up other
 ## orchestration services
-version: '2'
+version: '3'
 
 services:
 
   server:
-    image: szurubooru/server:latest
-    depends_on:
-      - sql
+    # image: szurubooru/server:latest
+    build:
+      context: ./server
+#    depends_on:
+#      - sql
     environment:
       ## These should be the names of the dependent containers listed below,
       ## or FQDNs/IP addresses if these services are running outside of Docker
-      POSTGRES_HOST: sql
+      POSTGRES_HOST: 192.168.1.17
       ## Credentials for database:
-      POSTGRES_USER:
-      POSTGRES_PASSWORD:
+      POSTGRES_USER: stash_u
+      POSTGRES_PASSWORD: tGmwRgEHbziNNEdsvcXynudFayVayzBybFvmMw
       ## Commented Values are Default:
-      #POSTGRES_DB: defaults to same as POSTGRES_USER
-      #POSTGRES_PORT: 5432
+      POSTGRES_DB: stash_db
+      POSTGRES_PORT: 5432
       #LOG_SQL: 0 (1 for verbose SQL logs)
       THREADS:
     volumes:
       - "${MOUNT_DATA}:/data"
       - "./server/config.yaml:/opt/app/config.yaml"
+      - "${MOUNT_SQL}:/var/lib/postgresql/data"
+    networks:
+       - br0
 
   client:
-    image: szurubooru/client:latest
+    # image: szurubooru/client:latest
+    build:
+      context: ./client
     depends_on:
       - server
     environment:
@@ -36,13 +43,22 @@ services:
     volumes:
       - "${MOUNT_DATA}:/data:ro"
     ports:
-      - "${PORT}:80"
+      - "${PORT}:8069"
+    networks:
+      - br0
 
-  sql:
-    image: postgres:11-alpine
-    restart: unless-stopped
-    environment:
-      POSTGRES_USER:
-      POSTGRES_PASSWORD:
-    volumes:
-      - "${MOUNT_SQL}:/var/lib/postgresql/data"
+  #sql:
+   # image: postgres:11-alpine
+    #restart: unless-stopped
+    #environment:
+     # POSTGRES_USER: stash_u
+      #POSTGRES_PASSWORD: TeKeuubttpyLtYHtkdvixgvyKqvfmeWuSkXcKp
+    #volumes:
+     # - "${MOUNT_SQL}:/var/lib/postgresql/data"
+    #networks:
+     # - temposvision
+
+networks:
+  br0:
+    external: true
+    name: br0
\ No newline at end of file
diff --git a/server/Dockerfile b/server/Dockerfile
index 3e4dadfb..35281d5a 100644
--- a/server/Dockerfile
+++ b/server/Dockerfile
@@ -24,14 +24,21 @@ RUN apk --no-cache add \
         py3-pynacl \
         py3-tz \
         py3-pyrfc3339
-RUN pip3 install --no-cache-dir --disable-pip-version-check \
+		
+# Upgrade pip and setuptools
+RUN pip3 install --no-cache-dir --disable-pip-version-check --upgrade pip setuptools wheel
+
+# Install required Python packages with PEP 517 disabled
+RUN pip3 install --no-cache-dir --disable-pip-version-check --no-build-isolation \
         "alembic>=0.8.5" \
         "coloredlogs==5.0" \
         "pyheif==0.6.1" \
         "heif-image-plugin>=0.3.2" \
-        yt-dlp \
-        "pillow-avif-plugin~=1.1.0"
-RUN apk --no-cache del py3-pip
+        youtube_dl \
+        "pillow-avif-plugin>=1.1.0"
+
+# Debugging: Print the installed packages
+RUN apk list --installed
 
 COPY ./ /opt/app/
 RUN rm -rf /opt/app/szurubooru/tests
@@ -75,6 +82,8 @@ RUN apk --no-cache add \
  && addgroup -g ${PGID} app \
  && adduser -SDH -h /opt/app -g '' -G app -u ${PUID} app \
  && chown -R app:app /opt/app /data
+ 
+RUN chmod +x /opt/app/docker-start.sh
 
 USER app
 CMD ["/opt/app/docker-start.sh"]
diff --git a/server/Dockerfile - Copy b/server/Dockerfile - Copy
new file mode 100644
index 00000000..70d36dbb
--- /dev/null
+++ b/server/Dockerfile - Copy	
@@ -0,0 +1,115 @@
+ARG ALPINE_VERSION=3.14
+
+
+FROM alpine:$ALPINE_VERSION as prereqs
+WORKDIR /opt/app
+
+RUN apk --no-cache add py3-pip build-base python3-dev libffi-dev libheif-dev \
+    && pip3 install --no-cache-dir --disable-pip-version-check --upgrade cffi \
+    && pip3 install --no-cache-dir --disable-pip-version-check --upgrade pyheif-pillow-opener \
+    && apk --no-cache del py3-pip build-base python3-dev libffi-dev libheif-dev \
+    && apk --no-cache add python3 python3-dev ffmpeg openssl-dev py3-pip py3-yaml py3-psycopg2 py3-sqlalchemy py3-certifi py3-numpy py3-pillow py3-pynacl py3-tz py3-pyrfc3339 build-base \
+    && apk --no-cache add libheif libavif libheif-dev libavif-dev \
+    && pip3 install --upgrade --disable-pip-version-check wheel alembic "coloredlogs==5.0" youtube_dl pillow-avif-plugin pyheif-pillow-opener \
+    && apk --no-cache del py3-pip
+
+
+RUN apk --no-cache add \
+        python3 \
+        python3-dev \
+        ffmpeg \
+		openssl-dev \
+        py3-pip \
+        # from requirements.txt:
+        py3-yaml \
+        py3-psycopg2 \
+        py3-sqlalchemy \
+        py3-certifi \
+        py3-numpy \
+        py3-pillow \
+        py3-pynacl \
+        py3-tz \
+        py3-pyrfc3339 \
+        build-base \
+ && apk --no-cache add \
+        libheif \
+        libavif \
+        libheif-dev \
+        libavif-dev \
+ && pip3 install --upgrade --disable-pip-version-check \
+		wheel \
+        alembic \
+        "coloredlogs==5.0" \
+        youtube_dl \
+        pillow-avif-plugin \
+        pyheif-pillow-opener \
+ && apk --no-cache del py3-pip
+
+COPY ./ /opt/app/
+RUN rm -rf /opt/app/szurubooru/tests
+
+
+FROM prereqs as testing
+WORKDIR /opt/app
+
+RUN apk --no-cache add \
+        py3-pip \
+        py3-pytest \
+        py3-pytest-cov \
+        postgresql \
+ && pip3 install --no-cache-dir --disable-pip-version-check \
+        pytest-pgsql \
+        freezegun \
+ && apk --no-cache del py3-pip \
+ && addgroup app \
+ && adduser -SDH -h /opt/app -g '' -G app app \
+ && chown app:app /opt/app
+
+COPY --chown=app:app ./szurubooru/tests /opt/app/szurubooru/tests/
+
+ENV TEST_ENVIRONMENT="true"
+USER app
+ENTRYPOINT ["pytest", "--tb=short"]
+CMD ["szurubooru/"]
+
+
+FROM prereqs as release
+WORKDIR /opt/app
+
+ARG PUID=1000
+ARG PGID=1000
+
+RUN apk --no-cache add \
+        dumb-init \
+        py3-setuptools \
+        py3-waitress \
+ && mkdir -p /opt/app /data \
+ && addgroup -g ${PGID} app \
+ && adduser -SDH -h /opt/app -g '' -G app -u ${PUID} app \
+ && chown -R app:app /opt/app /data
+
+
+
+RUN chmod +x /opt/app/docker-start.sh
+
+USER app
+CMD ["/opt/app/docker-start.sh"]
+
+ARG PORT=6666
+ENV PORT=${PORT}
+EXPOSE ${PORT}
+
+VOLUME ["/data/"]
+
+ARG DOCKER_REPO
+ARG BUILD_DATE
+ARG SOURCE_COMMIT
+LABEL \
+    maintainer="" \
+    org.opencontainers.image.title="${DOCKER_REPO}" \
+    org.opencontainers.image.url="https://github.com/rr-/szurubooru" \
+    org.opencontainers.image.documentation="https://github.com/rr-/szurubooru/blob/${SOURCE_COMMIT}/doc/INSTALL.md" \
+    org.opencontainers.image.created="${BUILD_DATE}" \
+    org.opencontainers.image.source="https://github.com/rr-/szurubooru" \
+    org.opencontainers.image.revision="${SOURCE_COMMIT}" \
+    org.opencontainers.image.licenses="GPL-3.0"
diff --git a/server/Dockerfile - Copy (2) b/server/Dockerfile - Copy (2)
new file mode 100644
index 00000000..8d535c8b
--- /dev/null
+++ b/server/Dockerfile - Copy (2)	
@@ -0,0 +1,104 @@
+ARG ALPINE_VERSION=3.13
+
+
+FROM alpine:$ALPINE_VERSION as prereqs
+WORKDIR /opt/app
+
+RUN apk --no-cache add \
+        python3 \
+        python3-dev \
+        py3-pip \
+        build-base \
+        libheif \
+        libheif-dev \
+        libavif \
+        libavif-dev \
+        ffmpeg \
+        # from requirements.txt:
+        py3-yaml \
+        py3-psycopg2 \
+        py3-sqlalchemy \
+        py3-certifi \
+        py3-numpy \
+        py3-pillow \
+        py3-pynacl \
+        py3-tz \
+        py3-pyrfc3339 \
+ && pip3 install --no-cache-dir --disable-pip-version-check \
+        "alembic>=0.8.5" \
+        "coloredlogs==5.0" \
+        "pyheif==0.6.1" \
+        "heif-image-plugin>=0.3.2" \
+        youtube_dl \
+        "pillow-avif-plugin>=1.1.0" \
+ && apk --no-cache del py3-pip
+
+COPY ./ /opt/app/
+RUN rm -rf /opt/app/szurubooru/tests
+
+
+FROM --platform=$BUILDPLATFORM prereqs as testing
+WORKDIR /opt/app
+
+RUN apk --no-cache add \
+        py3-pip \
+        py3-pytest \
+        py3-pytest-cov \
+        postgresql \
+ && pip3 install --no-cache-dir --disable-pip-version-check \
+        pytest-pgsql \
+        freezegun \
+ && apk --no-cache del py3-pip \
+ && addgroup app \
+ && adduser -SDH -h /opt/app -g '' -G app app \
+ && chown app:app /opt/app
+
+COPY --chown=app:app ./szurubooru/tests /opt/app/szurubooru/tests/
+
+ENV TEST_ENVIRONMENT="true"
+USER app
+ENTRYPOINT ["pytest", "--tb=short"]
+CMD ["szurubooru/"]
+
+
+FROM prereqs as release
+WORKDIR /opt/app
+
+ARG PUID=1000
+ARG PGID=1000
+
+RUN apk --no-cache add \
+        dumb-init \
+        py3-setuptools \
+        py3-waitress \
+ && mkdir -p /opt/app /data \
+ && addgroup -g ${PGID} app \
+ && adduser -SDH -h /opt/app -g '' -G app -u ${PUID} app \
+ && chown -R app:app /opt/app /data
+ 
+RUN chmod +x /opt/app/docker-start.sh
+
+USER app
+CMD ["/opt/app/docker-start.sh"]
+
+ARG PORT=6666
+ENV PORT=${PORT}
+EXPOSE ${PORT}
+
+ARG THREADS=4
+ENV THREADS=${THREADS}
+
+VOLUME ["/data/"]
+
+ARG DOCKER_REPO
+ARG BUILD_DATE
+ARG SOURCE_COMMIT
+LABEL \
+    maintainer="" \
+    org.opencontainers.image.title="${DOCKER_REPO}" \
+    org.opencontainers.image.url="https://github.com/rr-/szurubooru" \
+    org.opencontainers.image.documentation="https://github.com/rr-/szurubooru/blob/${SOURCE_COMMIT}/doc/INSTALL.md" \
+    org.opencontainers.image.created="${BUILD_DATE}" \
+    org.opencontainers.image.source="https://github.com/rr-/szurubooru" \
+    org.opencontainers.image.revision="${SOURCE_COMMIT}" \
+    org.opencontainers.image.licenses="GPL-3.0"
diff --git a/server/docker-start.sh b/server/docker-start.sh
index eebef1c7..314c355e 100755
--- a/server/docker-start.sh
+++ b/server/docker-start.sh
@@ -2,7 +2,7 @@
 set -e
 cd /opt/app
 
-alembic upgrade head
+alembic upgrade heads
 
-echo "Starting szurubooru API on port ${PORT} - Running on ${THREADS} threads"
-exec waitress-serve-3 --port ${PORT} --threads ${THREADS} szurubooru.facade:app
+echo "Starting szurubooru API on port ${PORT}"
+exec waitress-serve-3 --port ${PORT} szurubooru.facade:app
diff --git a/server/hooks/build b/server/hooks/build
new file mode 100644
index 00000000..b5e914b2
--- /dev/null
+++ b/server/hooks/build
@@ -0,0 +1,7 @@
+#!/bin/sh
+
+docker build \
+    --build-arg BUILD_DATE=$(date -u +'%Y-%m-%dT%H:%M:%SZ') \
+    --build-arg SOURCE_COMMIT \
+    --build-arg DOCKER_REPO \
+    -f $DOCKERFILE_PATH -t $IMAGE_NAME .
diff --git a/server/hooks/post_push b/server/hooks/post_push
new file mode 100644
index 00000000..1b1e0ad9
--- /dev/null
+++ b/server/hooks/post_push
@@ -0,0 +1,19 @@
+#!/bin/sh
+
+add_tag() {
+    echo "Also tagging image as ${DOCKER_REPO}:${1}"
+    docker tag $IMAGE_NAME $DOCKER_REPO:$1
+    docker push $DOCKER_REPO:$1
+}
+
+CLOSEST_VER=$(git describe --tags --abbrev=0)
+CLOSEST_MAJOR_VER=$(echo ${CLOSEST_VER} | cut -d'.' -f1)
+CLOSEST_MINOR_VER=$(echo ${CLOSEST_VER} | cut -d'.' -f2)
+
+add_tag "${CLOSEST_MAJOR_VER}-edge"
+add_tag "${CLOSEST_MAJOR_VER}.${CLOSEST_MINOR_VER}-edge"
+
+if git describe --exact-match --abbrev=0 2> /dev/null; then
+    add_tag "${CLOSEST_MAJOR_VER}"
+    add_tag "${CLOSEST_MAJOR_VER}.${CLOSEST_MINOR_VER}"
+fi
diff --git a/server/hooks/test b/server/hooks/test
new file mode 100644
index 00000000..b3251864
--- /dev/null
+++ b/server/hooks/test
@@ -0,0 +1,8 @@
+#!/bin/sh
+set -e
+
+docker run --rm \
+    -t $(docker build --target testing -q .) \
+    --color=no szurubooru/
+
+exit $?
diff --git a/server/requirements.txt b/server/requirements.txt
index ffe18f0c..16b29fff 100644
--- a/server/requirements.txt
+++ b/server/requirements.txt
@@ -3,7 +3,7 @@ certifi>=2017.11.5
 coloredlogs==5.0
 heif-image-plugin==0.3.2
 numpy>=1.8.2
-pillow-avif-plugin~=1.1.0
+pillow-avif-plugin>=1.1.0
 pillow>=4.3.0
 psycopg2-binary>=2.6.1
 pyheif==0.6.1
@@ -12,4 +12,4 @@ pyRFC3339>=1.0
 pytz>=2018.3
 pyyaml>=3.11
 SQLAlchemy>=1.0.12, <1.4
-yt-dlp
+youtube_dl
diff --git a/server/szurubooru/api/metric_api.py b/server/szurubooru/api/metric_api.py
new file mode 100644
index 00000000..2bba66f6
--- /dev/null
+++ b/server/szurubooru/api/metric_api.py
@@ -0,0 +1,94 @@
+from math import ceil
+from typing import Optional, List, Dict
+from szurubooru import db, model, search, rest
+from szurubooru.func import (
+    auth, metrics, snapshots, serialization, tags, versions
+)
+
+
+_search_executor_config = search.configs.PostMetricSearchConfig()
+_search_executor = search.Executor(_search_executor_config)
+
+
+def _serialize_metric(
+        ctx: rest.Context, metric: model.Metric) -> rest.Response:
+    return metrics.serialize_metric(
+        metric, options=serialization.get_serialization_options(ctx)
+    )
+
+
+def _serialize_post_metric(
+        ctx: rest.Context, post_metric: model.PostMetric) -> rest.Response:
+    return metrics.serialize_post_metric(
+        post_metric, options=serialization.get_serialization_options(ctx)
+    )
+
+
+def _get_metric(params: Dict[str, str]) -> model.Metric:
+    return metrics.get_metric_by_tag_name(params["tag_name"])
+
+
+@rest.routes.get("/metrics/?")
+def get_metrics(
+        ctx: rest.Context, params: Dict[str, str] = {}) -> rest.Response:
+    auth.verify_privilege(ctx.user, "metrics:list")
+    all_metrics = metrics.get_all_metrics()
+    return {
+        "results": [_serialize_metric(ctx, metric) for metric in all_metrics]
+    }
+
+
+@rest.routes.post("/metrics/?")
+def create_metric(
+        ctx: rest.Context, params: Dict[str, str] = {}) -> rest.Response:
+    auth.verify_privilege(ctx.user, "metrics:create")
+    tag_name = ctx.get_param_as_string("tag_name")
+    tag = tags.get_tag_by_name(tag_name)
+    min = ctx.get_param_as_float("min")
+    max = ctx.get_param_as_float("max")
+
+    metric = metrics.create_metric(tag, min, max)
+    ctx.session.flush()
+    # snapshots.create(metric, ctx.user)
+    ctx.session.commit()
+    return _serialize_metric(ctx, metric)
+
+
+@rest.routes.delete("/metric/(?P<tag_name>.+)")
+def delete_metric(ctx: rest.Context, params: Dict[str, str]) -> rest.Response:
+    metric = _get_metric(params)
+    versions.verify_version(metric, ctx)
+    auth.verify_privilege(ctx.user, "metrics:delete")
+    # snapshots.delete(metric, ctx.user)
+    metrics.delete_metric(metric)
+    ctx.session.commit()
+    return {}
+
+
+@rest.routes.get("/post-metrics/?")
+def get_post_metrics(
+        ctx: rest.Context, params: Dict[str, str] = {}) -> rest.Response:
+    auth.verify_privilege(ctx.user, "metrics:list")
+    return _search_executor.execute_and_serialize(
+        ctx, lambda post_metric: _serialize_post_metric(ctx, post_metric))
+
+
+@rest.routes.get("/post-metrics/median/(?P<tag_name>.+)")
+def get_post_metrics_median(
+        ctx: rest.Context, params: Dict[str, str] = {}) -> rest.Response:
+    auth.verify_privilege(ctx.user, "metrics:list")
+    metric = _get_metric(params)
+    tag_name = params["tag_name"]
+    query_text = ctx.get_param_as_string(
+        "query",
+        default="%s:%f..%f" % (tag_name, metric.min, metric.max))
+    total_count = _search_executor.count(query_text)
+    offset = ceil(total_count/2) - 1
+    _, results = _search_executor.execute(query_text, offset, 1)
+    return {
+        "query": query_text,
+        "offset": offset,
+        "limit": 1,
+        "total": len(results),
+        "results": list([_serialize_post_metric(ctx, pm) for pm in results])
+    }
diff --git a/server/szurubooru/func/metrics.py b/server/szurubooru/func/metrics.py
new file mode 100644
index 00000000..944c4d58
--- /dev/null
+++ b/server/szurubooru/func/metrics.py
@@ -0,0 +1,273 @@
+import sqlalchemy as sa
+from typing import Any, Optional, List, Dict, Callable
+from szurubooru import db, model, errors, rest
+from szurubooru.func import serialization, tags, util, versions
+
+
+class MetricDoesNotExistsError(errors.ValidationError):
+    pass
+
+
+class MetricAlreadyExistsError(errors.ValidationError):
+    pass
+
+
+class InvalidMetricError(errors.ValidationError):
+    pass
+
+
+class PostMissingTagError(errors.ValidationError):
+    pass
+
+
+class MetricValueOutOfRangeError(errors.ValidationError):
+    pass
+
+
+class MetricSerializer(serialization.BaseSerializer):
+    def __init__(self, metric: model.Metric):
+        self.metric = metric
+
+    def _serializers(self) -> Dict[str, Callable[[], Any]]:
+        return {
+            "version": lambda: self.metric.version,
+            "min": lambda: self.metric.min,
+            "max": lambda: self.metric.max,
+            "exact_count": lambda: self.metric.post_metric_count,
+            "range_count": lambda: self.metric.post_metric_range_count,
+            "tag": lambda: tags.serialize_tag(self.metric.tag, [
+                "names", "category", "description", "usages"])
+        }
+
+
+class PostMetricSerializer(serialization.BaseSerializer):
+    def __init__(self, post_metric: model.PostMetric):
+        self.post_metric = post_metric
+
+    def _serializers(self) -> Dict[str, Callable[[], Any]]:
+        return {
+            "tag_name": lambda: self.post_metric.metric.tag_name,
+            "post_id": lambda: self.post_metric.post_id,
+            "value": lambda: self.post_metric.value,
+        }
+
+
+class PostMetricRangeSerializer(serialization.BaseSerializer):
+    def __init__(self, post_metric_range: model.PostMetricRange):
+        self.post_metric_range = post_metric_range
+
+    def _serializers(self) -> Dict[str, Callable[[], Any]]:
+        return {
+            "tag_name": lambda: self.post_metric_range.metric.tag_name,
+            "post_id": lambda: self.post_metric_range.post_id,
+            "low": lambda: self.post_metric_range.low,
+            "high": lambda: self.post_metric_range.high,
+        }
+
+
+def serialize_metric(
+        metric: model.Metric,
+        options: List[str] = []) -> Optional[rest.Response]:
+    if not metric:
+        return None
+    return MetricSerializer(metric).serialize(options)
+
+
+def serialize_post_metric(
+        post_metric: model.PostMetric,
+        options: List[str] = []) -> Optional[rest.Response]:
+    if not post_metric:
+        return None
+    return PostMetricSerializer(post_metric).serialize(options)
+
+
+def serialize_post_metric_range(
+        post_metric_range: model.PostMetricRange,
+        options: List[str] = []) -> Optional[rest.Response]:
+    if not post_metric_range:
+        return None
+    return PostMetricRangeSerializer(post_metric_range).serialize(options)
+
+
+def try_get_metric_by_tag_name(tag_name: str) -> Optional[model.Metric]:
+    return (
+        db.session
+        .query(model.Metric)
+        .filter(sa.func.lower(model.Metric.tag_name) == tag_name.lower())
+        .one_or_none())
+
+
+def get_metric_by_tag_name(tag_name: str) -> model.Metric:
+    metric = try_get_metric_by_tag_name(tag_name)
+    if not metric:
+        raise MetricDoesNotExistsError("Metric %r not found." % tag_name)
+    return metric
+
+
+def get_all_metrics() -> List[model.Metric]:
+    return db.session.query(model.Metric).all()
+
+
+def get_all_metric_tag_names() -> List[str]:
+    return [
+        tag_name.name for tag_name in util.flatten_list(
+            [metric.tag.names for metric in get_all_metrics()]
+        )
+    ]
+
+
+def try_get_post_metric(
+        post: model.Post,
+        metric: model.Metric) -> Optional[model.PostMetric]:
+    return (
+        db.session
+        .query(model.PostMetric)
+        .filter(model.PostMetric.metric == metric)
+        .filter(model.PostMetric.post == post)
+        .one_or_none())
+
+
+def try_get_post_metric_range(
+        post: model.Post,
+        metric: model.Metric) -> Optional[model.PostMetricRange]:
+    return (
+        db.session
+        .query(model.PostMetricRange)
+        .filter(model.PostMetricRange.metric == metric)
+        .filter(model.PostMetricRange.post == post)
+        .one_or_none())
+
+
+def create_metric(
+        tag: model.Tag,
+        min: float,
+        max: float) -> model.Metric:
+    assert tag
+    if tag.metric:
+        raise MetricAlreadyExistsError("Tag already has a metric.")
+    if min >= max:
+        raise InvalidMetricError("Metric min(%r) >= max(%r)" % (min, max))
+    metric = model.Metric(tag=tag, min=min, max=max)
+    db.session.add(metric)
+    return metric
+
+
+def update_or_create_metric(
+        tag: model.Tag,
+        metric_data: Any) -> Optional[model.Metric]:
+    assert tag
+    for field in ("min", "max"):
+        if field not in metric_data:
+            raise InvalidMetricError("Metric is missing %r field." % field)
+
+    min, max = metric_data["min"], metric_data["max"]
+    if min >= max:
+        raise InvalidMetricError("Metric min(%r) >= max(%r)" % (min, max))
+    if tag.metric:
+        tag.metric.min = min
+        tag.metric.max = max
+        versions.bump_version(tag.metric)
+        return None
+    else:
+        return create_metric(tag=tag, min=min, max=max)
+
+
+def update_or_create_post_metric(
+        post: model.Post,
+        metric: model.Metric,
+        value: float) -> model.PostMetric:
+    assert post
+    assert metric
+    if metric.tag not in post.tags:
+        raise PostMissingTagError(
+            "Post doesn\"t have this tag.")
+    if value < metric.min or value > metric.max:
+        raise MetricValueOutOfRangeError(
+            "Metric value %r out of range." % value)
+    post_metric = try_get_post_metric(post, metric)
+    if not post_metric:
+        post_metric = model.PostMetric(post=post, metric=metric, value=value)
+        db.session.add(post_metric)
+    else:
+        post_metric.value = value
+        versions.bump_version(post_metric)
+    return post_metric
+
+
+def update_or_create_post_metrics(post: model.Post, metrics_data: Any) -> None:
+    """
+    Overwrites any existing post metrics, deletes other existing post metrics.
+    """
+    assert post
+    post.metrics = []
+    for metric_data in metrics_data:
+        for field in ("tag_name", "value"):
+            if field not in metric_data:
+                raise InvalidMetricError("Metric is missing %r field." % field)
+        value = float(metric_data["value"])
+        tag_name = metric_data["tag_name"]
+        tag = tags.get_tag_by_name(tag_name)
+        if not tag.metric:
+            raise MetricDoesNotExistsError(
+                "Tag %r has no metric." % tag_name)
+        post_metric = update_or_create_post_metric(post, tag.metric, value)
+        post.metrics.append(post_metric)
+
+
+def update_or_create_post_metric_range(
+        post: model.Post,
+        metric: model.Metric,
+        low: float,
+        high: float) -> model.PostMetricRange:
+    assert post
+    assert metric
+    if metric.tag not in post.tags:
+        raise PostMissingTagError(
+            "Post doesn\"t have this tag.")
+    for value in (low, high):
+        if value < metric.min or value > metric.max:
+            raise MetricValueOutOfRangeError(
+                "Metric value %r out of range." % value)
+    if low >= high:
+        raise InvalidMetricError(
+            "Metric range low(%r) >= high(%r)" % (low, high))
+    post_metric_range = try_get_post_metric_range(post, metric)
+    if not post_metric_range:
+        post_metric_range = model.PostMetricRange(
+            post=post, metric=metric, low=low, high=high)
+        db.session.add(post_metric_range)
+    else:
+        post_metric_range.low = low
+        post_metric_range.high = high
+        versions.bump_version(post_metric_range)
+    return post_metric_range
+
+
+def update_or_create_post_metric_ranges(
+        post: model.Post,
+        metric_ranges_data: Any) -> None:
+    """
+    Overwrites any existing post metrics, deletes other existing post metrics.
+    """
+    assert post
+    post.metric_ranges = []
+    for metric_data in metric_ranges_data:
+        for field in ("tag_name", "low", "high"):
+            if field not in metric_data:
+                raise InvalidMetricError(
+                    "Metric range is missing %r field." % field)
+        low = float(metric_data["low"])
+        high = float(metric_data["high"])
+        tag_name = metric_data["tag_name"]
+        tag = tags.get_tag_by_name(tag_name)
+        if not tag.metric:
+            raise MetricDoesNotExistsError(
+                "Tag %r has no metric." % tag_name)
+        post_metric_range = update_or_create_post_metric_range(
+            post, tag.metric, low, high)
+        post.metric_ranges.append(post_metric_range)
+
+
+def delete_metric(metric: model.Metric) -> None:
+    assert metric
+    db.session.delete(metric)
diff --git a/server/szurubooru/func/net.py b/server/szurubooru/func/net.py
index d6aa95e9..c53a62eb 100644
--- a/server/szurubooru/func/net.py
+++ b/server/szurubooru/func/net.py
@@ -64,7 +64,7 @@ def download(url: str, use_video_downloader: bool = False) -> bytes:
 
 
 def _get_youtube_dl_content_url(url: str) -> str:
-    cmd = ["yt-dlp", "--format", "best", "--no-playlist"]
+    cmd = ["youtube-dl", "--format", "best", "--no-playlist"]
     if config.config["user_agent"]:
         cmd.extend(["--user-agent", config.config["user_agent"]])
     cmd.extend(["--get-url", url])
diff --git a/server/szurubooru/func/similar.py b/server/szurubooru/func/similar.py
new file mode 100644
index 00000000..a19b7d17
--- /dev/null
+++ b/server/szurubooru/func/similar.py
@@ -0,0 +1,32 @@
+from typing import List
+
+import sqlalchemy as sa
+
+from szurubooru import db, model, search
+
+_search_executor_config = search.configs.PostSearchConfig()
+_search_executor = search.Executor(_search_executor_config)
+
+
+# TODO(hunternif): this ignores the query, e.g. rating.
+# (But we're actually using a "similar" search query on the client anyway.)
+def find_similar_posts(
+    source_post: model.Post, limit: int, query_text: str = ''
+) -> List[model.Post]:
+    post_alias = sa.orm.aliased(model.Post)
+    pt_alias = sa.orm.aliased(model.PostTag)
+    result = (
+        db.session.query(post_alias)
+        .join(pt_alias, pt_alias.post_id == post_alias.post_id)
+        .filter(
+            sa.sql.or_(
+                pt_alias.tag_id == tag.tag_id for tag in source_post.tags
+            )
+        )
+        .filter(pt_alias.post_id != source_post.post_id)
+        .group_by(post_alias.post_id)
+        .order_by(sa.func.count(pt_alias.tag_id).desc())
+        .order_by(post_alias.post_id.desc())
+        .limit(limit)
+    )
+    return result
diff --git a/server/szurubooru/model/metric.py b/server/szurubooru/model/metric.py
new file mode 100644
index 00000000..530165ad
--- /dev/null
+++ b/server/szurubooru/model/metric.py
@@ -0,0 +1,141 @@
+import sqlalchemy as sa
+from szurubooru.model.base import Base
+from szurubooru.model.post import PostTag
+from szurubooru.model.tag import TagName
+
+
+class PostMetric(Base):
+    __tablename__ = 'post_metric'
+
+    post_id = sa.Column(
+        'post_id',
+        sa.Integer,
+        sa.ForeignKey('post.id'),
+        primary_key=True,
+        nullable=False,
+        index=True)
+    tag_id = sa.Column(
+        'tag_id',
+        sa.Integer,
+        sa.ForeignKey('metric.tag_id'),
+        primary_key=True,
+        nullable=False,
+        index=True)
+    version = sa.Column('version', sa.Integer, default=1, nullable=False)
+    value = sa.Column('value', sa.Float, nullable=False, index=True)
+
+    post = sa.orm.relationship('Post')
+    metric = sa.orm.relationship('Metric', back_populates='post_metrics')
+
+    __table_args__ = (sa.ForeignKeyConstraint(
+        (post_id, tag_id),
+        (PostTag.post_id, PostTag.tag_id),
+        ondelete='cascade'),
+    )
+    __mapper_args__ = {
+        'version_id_col': version,
+        'version_id_generator': False,
+        # when deleting tag or post, cascade will ensure this post metric is
+        # also deleted, but sqlalchemy will try to delete it twice because of
+        # the cascade on foreign key into PostTag. This silences the error:
+        'confirm_deleted_rows': False,
+    }
+
+
+class PostMetricRange(Base):
+    """
+    Could be a metric in the process of finding its exact value, e.g. by sorting.
+    It has upper and lower boundaries that will converge at the final value.
+    """
+    __tablename__ = 'post_metric_range'
+
+    post_id = sa.Column(
+        'post_id',
+        sa.Integer,
+        sa.ForeignKey('post.id'),
+        primary_key=True,
+        nullable=False,
+        index=True)
+    tag_id = sa.Column(
+        'tag_id',
+        sa.Integer,
+        sa.ForeignKey('metric.tag_id'),
+        primary_key=True,
+        nullable=False,
+        index=True)
+    version = sa.Column('version', sa.Integer, default=1, nullable=False)
+    low = sa.Column('low', sa.Float, nullable=False)
+    high = sa.Column('high', sa.Float, nullable=False)
+
+    post = sa.orm.relationship('Post')
+    metric = sa.orm.relationship('Metric', back_populates='post_metric_ranges')
+
+    __table_args__ = (sa.ForeignKeyConstraint(
+        (post_id, tag_id),
+        (PostTag.post_id, PostTag.tag_id),
+        ondelete='cascade'),
+    )
+    __mapper_args__ = {
+        'version_id_col': version,
+        'version_id_generator': False,
+        # when deleting tag or post, cascade will ensure this post metric is
+        # also deleted, but sqlalchemy will try to delete it twice because of
+        # the cascade on foreign key into PostTag. This silences the error:
+        'confirm_deleted_rows': False,
+    }
+
+
+class Metric(Base):
+    """
+    Must be attached to a tag, tag_id is primary key.
+    """
+    __tablename__ = 'metric'
+
+    tag_id = sa.Column(
+        'tag_id',
+        sa.Integer,
+        sa.ForeignKey('tag.id'),
+        primary_key=True,
+        nullable=False,
+        index=True)
+    version = sa.Column('version', sa.Integer, default=1, nullable=False)
+    min = sa.Column('min', sa.Float, nullable=False)
+    max = sa.Column('max', sa.Float, nullable=False)
+
+    tag = sa.orm.relationship('Tag')
+    post_metrics = sa.orm.relationship(
+        'PostMetric', back_populates='metric', cascade='all, delete-orphan')
+    post_metric_ranges = sa.orm.relationship(
+        'PostMetricRange', back_populates='metric', cascade='all, delete-orphan')
+
+    tag_name = sa.orm.column_property(
+        (
+            sa.sql.expression.select([TagName.name])
+                .where(TagName.tag_id == tag_id)
+                .order_by(TagName.order)
+                .limit(1)
+                .as_scalar()
+        ))
+
+    post_metric_count = sa.orm.column_property(
+        (
+            sa.sql.expression.select(
+                [sa.sql.expression.func.count(PostMetric.post_id)])
+                .where(PostMetric.tag_id == tag_id)
+                .correlate_except(PostMetric)
+        ),
+        deferred=True)
+
+    post_metric_range_count = sa.orm.column_property(
+        (
+            sa.sql.expression.select(
+                [sa.sql.expression.func.count(PostMetricRange.post_id)])
+                .where(PostMetricRange.tag_id == tag_id)
+                .correlate_except(PostMetricRange)
+        ),
+        deferred=True)
+
+    __mapper_args__ = {
+        'version_id_col': version,
+        'version_id_generator': False,
+    }
diff --git a/server/szurubooru/search/configs/post_metric_search_config.py b/server/szurubooru/search/configs/post_metric_search_config.py
new file mode 100644
index 00000000..0cdb1ea2
--- /dev/null
+++ b/server/szurubooru/search/configs/post_metric_search_config.py
@@ -0,0 +1,44 @@
+from typing import Dict
+
+import sqlalchemy as sa
+
+from szurubooru import db, model
+from szurubooru.func import metrics, util
+from szurubooru.search.configs import util as search_util
+from szurubooru.search.configs.base_search_config import (
+    BaseSearchConfig, Filter)
+from szurubooru.search.typing import SaQuery
+
+
+class PostMetricSearchConfig(BaseSearchConfig):
+    def __init__(self) -> None:
+        self.all_metric_names = []
+
+    def refresh_metrics(self) -> None:
+        self.all_metric_names = metrics.get_all_metric_tag_names()
+
+    def create_filter_query(self, _disable_eager_loads: bool) -> SaQuery:
+        self.refresh_metrics()
+        return db.session.query(model.PostMetric).options(sa.orm.lazyload('*'))
+
+    def create_count_query(self, disable_eager_loads: bool) -> SaQuery:
+        return self.create_filter_query(disable_eager_loads)
+
+    def create_around_query(self) -> SaQuery:
+        return self.create_filter_query()
+
+    def finalize_query(self, query: SaQuery) -> SaQuery:
+        return query.order_by(model.PostMetric.value.asc())
+
+    @property
+    def anonymous_filter(self) -> Filter:
+        return search_util.create_subquery_filter(
+            model.PostMetric.tag_id,
+            model.TagName.tag_id,
+            model.TagName.name,
+            search_util.create_str_filter)
+
+    @property
+    def named_filters(self) -> Dict[str, Filter]:
+        num_filter = search_util.create_float_filter(model.PostMetric.value)
+        return {tag_name: num_filter for tag_name in self.all_metric_names}
diff --git a/server/szurubooru/search/executor.py b/server/szurubooru/search/executor.py
index a5ef9625..7a64fc26 100644
--- a/server/szurubooru/search/executor.py
+++ b/server/szurubooru/search/executor.py
@@ -37,8 +37,7 @@ class Executor:
         self.parser = parser.Parser()
 
     def get_around(
-        self, query_text: str, entity_id: int
-    ) -> Tuple[model.Base, model.Base]:
+        self, query_text: str, entity_id: int) -> Tuple[model.Base, model.Base, model.Base]:
         search_query = self.parser.parse(query_text)
         self.config.on_search_query_parsed(search_query)
         filter_query = self.config.create_around_query().options(
@@ -57,11 +56,15 @@ class Executor:
             filter_query.filter(self.config.id_column < entity_id)
             .order_by(None)
             .order_by(sa.func.abs(self.config.id_column - entity_id).asc())
-            .limit(1)
-        )
+            .limit(1))
+        # random post
+        if 'sort:random' not in query_text:
+            query_text = query_text + ' sort:random'
+        count, random_entities = self.execute(query_text, 0, 1)
         return (
             prev_filter_query.one_or_none(),
             next_filter_query.one_or_none(),
+            random_entities[0] if random_entities else None
         )
 
     def get_around_and_serialize(
@@ -76,6 +79,7 @@ class Executor:
         return {
             "prev": serializer(entities[0]),
             "next": serializer(entities[1]),
+            'random': serializer(entities[2]),
         }
 
     def execute(
@@ -94,7 +98,7 @@ class Executor:
                 disable_eager_loads = True
 
         key = (id(self.config), hash(search_query), offset, limit)
-        if cache.has(key):
+        if not disable_eager_loads and cache.has(key):
             return cache.get(key)
 
         filter_query = self.config.create_filter_query(disable_eager_loads)
diff --git a/server/szurubooru/tests/api/test_metric_retrieving.py b/server/szurubooru/tests/api/test_metric_retrieving.py
new file mode 100644
index 00000000..81e29cd0
--- /dev/null
+++ b/server/szurubooru/tests/api/test_metric_retrieving.py
@@ -0,0 +1,63 @@
+from szurubooru import api, db, model
+
+import pytest
+
+
+@pytest.fixture(autouse=True)
+def inject_config(config_injector):
+    config_injector(
+        {
+            "privileges": {
+                "metrics:list": model.User.RANK_REGULAR,
+            },
+        }
+    )
+
+@pytest.mark.parametrize('query,expected_value', [
+    ('', 5),
+    ('mytag:0..', 5),
+    ('mytag:..10', 5),
+    ('mytag:0..10', 5),
+    ('mytag:2..8', 5),
+    ('mytag:0..8', 4),
+    ('mytag:0..6', 4),
+    ('mytag:0..5.5', 4),
+    ('mytag:0..4', 1),
+    ('mytag:1..4', 1),
+    ('mytag:2..3', None),
+])
+def test_median(
+        query,
+        expected_value,
+        tag_factory,
+        post_factory,
+        metric_factory,
+        post_metric_factory,
+        context_factory,
+        user_factory):
+    tag = tag_factory(names=['mytag'])
+    post1 = post_factory(tags=[tag])
+    post4 = post_factory(tags=[tag])
+    post5 = post_factory(tags=[tag])
+    post6 = post_factory(tags=[tag])
+    post10 = post_factory(tags=[tag])
+    metric = metric_factory(tag=tag, min=0, max=10)
+    pm1 = post_metric_factory(metric=metric, post=post1, value=1)
+    pm4 = post_metric_factory(metric=metric, post=post4, value=4)
+    pm5 = post_metric_factory(metric=metric, post=post5, value=5)
+    pm6 = post_metric_factory(metric=metric, post=post6, value=6)
+    pm10 = post_metric_factory(metric=metric, post=post10, value=10)
+    db.session.add_all([tag, metric, pm1, pm4, pm5, pm6, pm10,
+                        post1, post4, post5, post6, post10])
+    db.session.flush()
+    response = api.metric_api.get_post_metrics_median(
+        context_factory(
+            params={'query': query},
+            user=user_factory(rank=model.User.RANK_REGULAR)),
+        {'tag_name': 'mytag'})
+    if not expected_value:
+        assert response['total'] == 0
+        assert len(response['results']) == 0
+    else:
+        assert response['total'] == 1
+        assert response['results'][0]['value'] == expected_value
diff --git a/server/szurubooru/tests/func/test_metrics.py b/server/szurubooru/tests/func/test_metrics.py
new file mode 100644
index 00000000..c33be623
--- /dev/null
+++ b/server/szurubooru/tests/func/test_metrics.py
@@ -0,0 +1,459 @@
+import pytest
+from szurubooru import db, model
+from szurubooru.func import metrics
+
+
+def test_serialize_metric(tag_category_factory, tag_factory):
+    cat = tag_category_factory(name="cat")
+    tag = tag_factory(names=["tag1"], category=cat)
+    metric = model.Metric(tag=tag, min=1, max=2)
+    db.session.add(metric)
+    db.session.flush()
+    result = metrics.serialize_metric(metric)
+    assert result == {
+        "version": 1,
+        "min": 1,
+        "max": 2,
+        "exact_count": 0,
+        "range_count": 0,
+        "tag": {
+            "names": ["tag1"],
+            "category": "cat",
+            "description": None,
+            "usages": 0,
+        },
+    }
+
+
+def test_serialize_post_metric(post_factory, tag_factory, metric_factory):
+    tag = tag_factory(names=["mytag"])
+    post = post_factory(id=456, tags=[tag])
+    metric = metric_factory(tag)
+    post_metric = model.PostMetric(post=post, metric=metric, value=-12.3)
+    db.session.add_all([post, tag, metric, post_metric])
+    db.session.flush()
+    result = metrics.serialize_post_metric(post_metric)
+    assert result == {
+        "tag_name": "mytag",
+        "post_id": 456,
+        "value": -12.3,
+    }
+
+
+def test_serialize_post_metric_range(post_factory, tag_factory, metric_factory):
+    tag = tag_factory(names=["mytag"])
+    post = post_factory(id=456, tags=[tag])
+    metric = metric_factory(tag)
+    post_metric_range = model.PostMetricRange(
+        post=post, metric=metric, low=-1.2, high=3.4)
+    db.session.add_all([post, tag, metric, post_metric_range])
+    db.session.flush()
+    result = metrics.serialize_post_metric_range(post_metric_range)
+    assert result == {
+        "tag_name": "mytag",
+        "post_id": 456,
+        "low": -1.2,
+        "high": 3.4
+    }
+
+
+def test_try_get_metric_by_tag_name(tag_factory, metric_factory):
+    tag = tag_factory(names=["mytag"])
+    metric = metric_factory(tag)
+    db.session.add_all([tag, metric])
+    db.session.flush()
+    assert metrics.try_get_metric_by_tag_name("unknown") is None
+    assert metrics.try_get_metric_by_tag_name("mytag") is metric
+
+
+def test_try_get_post_metric(
+        post_factory, metric_factory, post_metric_factory):
+    metric1 = metric_factory()
+    metric2 = metric_factory()
+    post = post_factory(tags=[metric1.tag, metric2.tag])
+    post_metric = post_metric_factory(post=post, metric=metric1)
+    db.session.add_all([post, metric1, metric2, post_metric])
+    db.session.flush()
+    assert metrics.try_get_post_metric(post, metric2) is None
+    assert metrics.try_get_post_metric(post, metric1) is post_metric
+
+
+def test_try_get_post_metric_range(
+        post_factory, metric_factory, post_metric_range_factory):
+    metric1 = metric_factory()
+    metric2 = metric_factory()
+    post = post_factory(tags=[metric1.tag, metric2.tag])
+    post_metric_range = post_metric_range_factory(post=post, metric=metric1)
+    db.session.add_all([post, metric1, metric2, post_metric_range])
+    db.session.flush()
+    assert metrics.try_get_post_metric_range(post, metric2) is None
+    assert metrics.try_get_post_metric_range(post, metric1) is post_metric_range
+
+
+def test_get_all_metrics(metric_factory):
+    metric1 = metric_factory()
+    metric2 = metric_factory()
+    metric3 = metric_factory()
+    db.session.add_all([metric1, metric2, metric3])
+    db.session.flush()
+    all_metrics = metrics.get_all_metrics()
+    assert len(all_metrics) == 3
+    assert metric1 in all_metrics
+    assert metric2 in all_metrics
+    assert metric3 in all_metrics
+
+
+def test_get_all_metric_tag_names(tag_factory, metric_factory):
+    tag1 = tag_factory(names=["abc", "def"])
+    tag2 = tag_factory(names=["ghi"])
+    metric1 = metric_factory(tag=tag1)
+    metric2 = metric_factory(tag=tag2)
+    db.session.add_all([metric1, metric2])
+    db.session.flush()
+    assert metrics.get_all_metric_tag_names() == ["abc", "def", "ghi"]
+
+
+def test_create_metric(tag_factory):
+    tag = tag_factory()
+    db.session.add(tag)
+    new_metric = metrics.create_metric(tag, 1, 2)
+    assert new_metric is not None
+    db.session.flush()
+    assert tag.metric is not None
+    assert tag.metric.min == 1
+    assert tag.metric.max == 2
+
+
+def test_create_metric_with_existing_metric(tag_factory):
+    tag = tag_factory()
+    tag.metric = model.Metric()
+    with pytest.raises(metrics.MetricAlreadyExistsError):
+        metrics.create_metric(tag, 1, 2)
+
+
+def test_create_metric_with_invalid_params(tag_factory):
+    tag = tag_factory()
+    with pytest.raises(metrics.InvalidMetricError):
+        metrics.create_metric(tag, 2, 1)
+
+
+def test_update_or_create_metric(tag_factory):
+    tag = tag_factory()
+    db.session.add(tag)
+    new_metric = metrics.update_or_create_metric(tag, {"min": 1, "max": 2})
+    assert new_metric is not None
+    db.session.flush()
+    assert tag.metric is not None
+    assert tag.metric.min == 1
+    assert tag.metric.max == 2
+    assert tag.metric.version == 1
+
+    new_metric = metrics.update_or_create_metric(tag, {"min": 3, "max": 4})
+    assert new_metric is None
+    db.session.flush()
+    assert tag.metric.min == 3
+    assert tag.metric.max == 4
+    assert tag.metric.version == 2
+
+
+@pytest.mark.parametrize("params", [
+    {"min": 1}, {"max": 2}, {"min": 2, "max": 1}
+])
+def test_update_or_create_metric_with_invalid_params(tag_factory, params):
+    tag = tag_factory()
+    with pytest.raises(metrics.InvalidMetricError):
+        metrics.update_or_create_metric(tag, params)
+
+
+# Post metrics
+
+def test_update_or_create_post_metric_without_tag(post_factory, metric_factory):
+    post = post_factory()
+    metric = metric_factory()
+    with pytest.raises(metrics.PostMissingTagError):
+        metrics.update_or_create_post_metric(post, metric, 1.5)
+
+
+def test_update_or_create_post_metric_with_value_out_of_range(
+        post_factory, metric_factory):
+    metric = metric_factory()
+    post = post_factory(tags=[metric.tag])
+    with pytest.raises(metrics.MetricValueOutOfRangeError):
+        metrics.update_or_create_post_metric(post, metric, -99)
+
+
+def test_update_or_create_post_metric_create(post_factory, metric_factory):
+    metric = metric_factory()
+    post = post_factory(tags=[metric.tag])
+    db.session.add(metric)
+    db.session.flush()
+    post_metric = metrics.update_or_create_post_metric(post, metric, 1.5)
+    assert post_metric.value == 1.5
+
+
+def test_update_or_create_post_metric_update(post_factory, metric_factory):
+    metric = metric_factory()
+    post1 = post_factory(tags=[metric.tag])
+    post2 = post_factory(tags=[metric.tag])
+    post_metric1 = model.PostMetric(post=post1, metric=metric, value=1.2)
+    post_metric2 = model.PostMetric(post=post2, metric=metric, value=5.6)
+    db.session.add_all([post1, post2, post_metric1, post_metric2])
+    db.session.flush()
+    assert post_metric1.version == 1
+    assert post_metric2.version == 1
+
+    metrics.update_or_create_post_metric(post1, metric, 3.4)
+    db.session.flush()
+
+    assert db.session.query(model.PostMetric).count() == 2
+    assert post_metric1.value == 3.4
+    assert post_metric1.version == 2
+    assert post_metric2.value == 5.6
+    assert post_metric2.version == 1
+
+
+def test_update_or_create_post_metrics_missing_tag(
+        post_factory, tag_factory, metric_factory):
+    post = post_factory()
+    tag = tag_factory(names=["tag1"])
+    metric = metric_factory(tag)
+    db.session.add(metric)
+    db.session.flush()
+    data = [{"tag_name": "tag1", "value": 1.5}]
+    with pytest.raises(metrics.PostMissingTagError):
+        metrics.update_or_create_post_metrics(post, data)
+
+
+@pytest.mark.parametrize("params", [
+    [{}],
+    [{"tag_name": "tag"}],
+    [{"value": 1.5}]
+])
+def test_update_or_create_post_metrics_with_missing_fields(
+        params, post_factory):
+    post = post_factory()
+    with pytest.raises(metrics.InvalidMetricError):
+        metrics.update_or_create_post_metrics(post, params)
+
+
+def test_update_or_create_post_metrics_with_invalid_tag(
+        post_factory, tag_factory):
+    tag = tag_factory(names=["tag1"])
+    post = post_factory(tags=[tag])
+    db.session.add(tag)
+    db.session.flush()
+    data = [{"tag_name": "tag1", "value": 2}]
+    with pytest.raises(metrics.MetricDoesNotExistsError):
+        metrics.update_or_create_post_metrics(post, data)
+
+
+def test_update_or_create_post_metrics(
+        post_factory, tag_factory, metric_factory):
+    tag1 = tag_factory(names=["tag1"])
+    tag2 = tag_factory(names=["tag2"])
+    post = post_factory(tags=[tag1, tag2])
+    metric1 = metric_factory(tag1)
+    metric2 = metric_factory(tag2)
+    db.session.add_all([metric1, metric2])
+    db.session.flush()
+
+    data = [
+        {"tag_name": "tag1", "value": 1.2},
+        {"tag_name": "tag2", "value": 3.4},
+    ]
+    metrics.update_or_create_post_metrics(post, data)
+    db.session.flush()
+
+    assert len(post.metrics) == 2
+    assert post.metrics[0].value == 1.2
+    assert post.metrics[1].value == 3.4
+
+
+def test_update_or_create_post_metrics_with_trim(
+        post_factory, tag_factory, metric_factory, post_metric_factory):
+    tag1 = tag_factory(names=["tag1"])
+    tag2 = tag_factory(names=["tag2"])
+    post = post_factory(tags=[tag1, tag2])
+    metric1 = metric_factory(tag1)
+    metric2 = metric_factory(tag2)
+    post_metric = post_metric_factory(post=post, metric=metric1, value=1.2)
+    db.session.add_all([post, tag1, tag2, metric1, metric2, post_metric])
+    db.session.flush()
+    assert len(post.metrics) == 1
+    assert post.metrics[0].metric == metric1
+    assert post.metrics[0].value == 1.2
+
+    data = [
+        {"tag_name": "tag2", "value": 3.4},
+    ]
+    metrics.update_or_create_post_metrics(post, data)
+    db.session.flush()
+
+    assert len(post.metrics) == 1
+    assert post.metrics[0].metric == metric2
+    assert post.metrics[0].value == 3.4
+
+
+# Post metric ranges
+
+def test_update_or_create_post_metric_range_without_tag(
+        post_factory, metric_factory):
+    post = post_factory()
+    metric = metric_factory()
+    with pytest.raises(metrics.PostMissingTagError):
+        metrics.update_or_create_post_metric_range(post, metric, 2, 3)
+
+
+@pytest.mark.parametrize("low, high", [
+    (-99, 1), (1, 99),
+])
+def test_update_or_create_post_metric_range_with_values_out_of_range(
+        low, high, post_factory, metric_factory):
+    metric = metric_factory()
+    post = post_factory(tags=[metric.tag])
+    with pytest.raises(metrics.MetricValueOutOfRangeError):
+        metrics.update_or_create_post_metric_range(post, metric, low, high)
+
+
+def test_update_or_create_post_metric_range_create(
+        post_factory, metric_factory):
+    metric = metric_factory()
+    post = post_factory(tags=[metric.tag])
+    db.session.add(metric)
+    db.session.flush()
+    post_metric_range = metrics.update_or_create_post_metric_range(
+        post, metric, 2, 3)
+    assert post_metric_range.low == 2
+    assert post_metric_range.high == 3
+
+
+def test_update_or_create_post_metric_range_update(
+        post_factory, metric_factory):
+    metric = metric_factory()
+    post = post_factory(tags=[metric.tag])
+    post_metric_range = model.PostMetricRange(
+        post=post, metric=metric, low=2, high=3)
+    db.session.add(post_metric_range)
+    db.session.flush()
+    assert post_metric_range.version == 1
+
+    metrics.update_or_create_post_metric_range(post, metric, 4, 5)
+    db.session.flush()
+
+    assert post_metric_range.low == 4
+    assert post_metric_range.high == 5
+    assert post_metric_range.version == 2
+
+
+def test_update_or_create_post_metric_ranges_missing_tag(
+        post_factory, tag_factory, metric_factory):
+    post = post_factory()
+    tag = tag_factory(names=["tag1"])
+    metric = metric_factory(tag)
+    db.session.add(metric)
+    db.session.flush()
+    data = [{"tag_name": "tag1", "low": 2, "high": 3}]
+    with pytest.raises(metrics.PostMissingTagError):
+        metrics.update_or_create_post_metric_ranges(post, data)
+
+
+@pytest.mark.parametrize("params", [
+    [{}],
+    [{"tag_name": "tag"}],
+    [{"tag_name": "tag", "low": 2}],
+    [{"low": 2, "high": 3}],
+])
+def test_update_or_create_post_metric_ranges_with_missing_fields(
+        params, post_factory, tag_factory):
+    tag = tag_factory(names=["tag"])
+    post = post_factory(tags=[tag])
+    with pytest.raises(metrics.InvalidMetricError):
+        metrics.update_or_create_post_metric_ranges(post, params)
+
+
+def test_update_or_create_post_metric_ranges_with_invalid_tag(
+        post_factory, tag_factory):
+    tag = tag_factory(names=["tag1"])
+    post = post_factory(tags=[tag])
+    db.session.add(tag)
+    db.session.flush()
+    data = [{"tag_name": "tag1", "low": 2, "high": 3}]
+    with pytest.raises(metrics.MetricDoesNotExistsError):
+        metrics.update_or_create_post_metric_ranges(post, data)
+
+
+def test_update_or_create_post_metric_ranges_with_invalid_values(
+        post_factory, tag_factory, metric_factory):
+    tag = tag_factory(names=["tag1"])
+    post = post_factory(tags=[tag])
+    metric = metric_factory(tag=tag)
+    db.session.add_all([metric, tag])
+    db.session.flush()
+    data = [
+        {"tag_name": "tag1", "low": 4, "high": 2},
+    ]
+    with pytest.raises(metrics.InvalidMetricError):
+        metrics.update_or_create_post_metric_ranges(post, data)
+
+
+def test_update_or_create_post_metric_ranges(
+        post_factory, tag_factory, metric_factory):
+    tag1 = tag_factory(names=["tag1"])
+    tag2 = tag_factory(names=["tag2"])
+    post = post_factory(tags=[tag1, tag2])
+    metric1 = metric_factory(tag1)
+    metric2 = metric_factory(tag2)
+    db.session.add_all([metric1, metric2])
+    db.session.flush()
+
+    data = [
+        {"tag_name": "tag1", "low": 2, "high": 3},
+        {"tag_name": "tag2", "low": 4, "high": 5},
+    ]
+    metrics.update_or_create_post_metric_ranges(post, data)
+    db.session.flush()
+
+    assert len(post.metric_ranges) == 2
+    assert post.metric_ranges[0].low == 2
+    assert post.metric_ranges[0].high == 3
+    assert post.metric_ranges[1].low == 4
+    assert post.metric_ranges[1].high == 5
+
+
+def test_update_or_create_post_metric_ranges_with_trim(
+        post_factory, tag_factory, metric_factory, post_metric_range_factory):
+    tag1 = tag_factory(names=["tag1"])
+    tag2 = tag_factory(names=["tag2"])
+    post = post_factory(tags=[tag1, tag2])
+    metric1 = metric_factory(tag1)
+    metric2 = metric_factory(tag2)
+    post_metric_range = post_metric_range_factory(
+        post=post, metric=metric1, low=1, high=2)
+    db.session.add_all([post, tag1, tag2, metric1, metric2, post_metric_range])
+    db.session.flush()
+    assert len(post.metric_ranges) == 1
+    assert post.metric_ranges[0].metric == metric1
+    assert post.metric_ranges[0].low == 1
+    assert post.metric_ranges[0].high == 2
+
+    data = [
+        {"tag_name": "tag2", "low": 3, "high": 4},
+    ]
+    metrics.update_or_create_post_metric_ranges(post, data)
+    db.session.flush()
+
+    assert len(post.metric_ranges) == 1
+    assert post.metric_ranges[0].metric == metric2
+    assert post.metric_ranges[0].low == 3
+    assert post.metric_ranges[0].high == 4
+
+
+def test_delete_metric(metric_factory):
+    metric1 = metric_factory()
+    metric2 = metric_factory()
+    db.session.add_all([metric1, metric2])
+    db.session.flush()
+    assert db.session.query(model.Metric).count() == 2
+    metrics.delete_metric(metric2)
+    db.session.flush()
+    assert db.session.query(model.Metric).count() == 1
diff --git a/server/szurubooru/tests/func/test_similar.py b/server/szurubooru/tests/func/test_similar.py
new file mode 100644
index 00000000..5346cb05
--- /dev/null
+++ b/server/szurubooru/tests/func/test_similar.py
@@ -0,0 +1,60 @@
+import pytest
+from szurubooru import db
+from szurubooru.func import similar
+
+
+@pytest.fixture
+def verify_posts():
+    def verify(actual_posts, expected_posts):
+        actual_post_ids = list([p.post_id for p in actual_posts])
+        expected_post_ids = list([p.post_id for p in expected_posts])
+        assert actual_post_ids == expected_post_ids
+
+    return verify
+
+
+def test_find_similar_posts(post_factory, tag_factory, verify_posts):
+    tagA = tag_factory(names=["a"])
+    tagB = tag_factory(names=["b"])
+    tagC = tag_factory(names=["c"])
+    postA = post_factory(id=1, tags=[tagA])
+    postAB = post_factory(id=2, tags=[tagA, tagB])
+    postAC = post_factory(id=3, tags=[tagA, tagC])
+    postABC = post_factory(id=4, tags=[tagA, tagB, tagC])
+    postBC = post_factory(id=5, tags=[tagB, tagC])
+    db.session.add_all([tagA, tagB, tagC, postA, postAB, postAC, postABC, postBC])
+    db.session.flush()
+
+    results = similar.find_similar_posts(postBC, 10)
+    verify_posts(results, [postABC, postAC, postAB])
+
+    results = similar.find_similar_posts(postBC, 2)
+    verify_posts(results, [postABC, postAC])
+
+    results = similar.find_similar_posts(postABC, 10)
+    verify_posts(results, [postBC, postAC, postAB, postA])
+
+    results = similar.find_similar_posts(postA, 10)
+    verify_posts(results, [postABC, postAC, postAB])  # sorted by id
+
+    results = similar.find_similar_posts(postAB, 10)
+    verify_posts(results, [postABC, postBC, postAC, postA])
+
+    results = similar.find_similar_posts(postAC, 10)
+    verify_posts(results, [postABC, postBC, postAB, postA])
+
+
+def test_find_similar_posts_with_limit(post_factory, tag_factory, verify_posts):
+    tagA = tag_factory(names=["a"])
+    tagB = tag_factory(names=["b"])
+    tagC = tag_factory(names=["c"])
+    tagD = tag_factory(names=["d"])
+    tagE = tag_factory(names=["e"])
+    postA = post_factory(id=111, tags=[tagA])
+    postAB = post_factory(id=112, tags=[tagA, tagB])
+    postABCDE = post_factory(id=113, tags=[tagA, tagB, tagC, tagD, tagE])
+    db.session.add_all([tagA, tagB, tagC, tagD, tagE, postA, postAB, postABCDE])
+    db.session.flush()
+
+    results = similar.find_similar_posts(postABCDE, 10)
+    verify_posts(results, [postAB, postA])
diff --git a/server/szurubooru/tests/model/test_metric.py b/server/szurubooru/tests/model/test_metric.py
new file mode 100644
index 00000000..cf0fa56d
--- /dev/null
+++ b/server/szurubooru/tests/model/test_metric.py
@@ -0,0 +1,235 @@
+from szurubooru import db, model
+
+import pytest
+
+@pytest.fixture(autouse=True)
+def inject_config(config_injector):
+    config_injector(
+        {"secret": "secret", "data_dir": "", "delete_source_files": False}
+    )
+
+def test_saving_metric(post_factory, tag_factory):
+    tag = tag_factory()
+    post = post_factory(tags=[tag])
+    metric = model.Metric(tag=tag, min=1., max=10.)
+    post_metric = model.PostMetric(metric=metric, post=post, value=5.5)
+    post_metric_range = model.PostMetricRange(metric=metric, post=post,
+                                              low=2., high=8.)
+    db.session.add_all([post, tag, metric, post_metric, post_metric_range])
+    db.session.commit()
+
+    assert metric.tag_id is not None
+    assert post_metric.tag_id is not None
+    assert post_metric.post_id is not None
+    assert post_metric_range.tag_id is not None
+    assert post_metric_range.post_id is not None
+    assert tag.metric.tag_id == tag.tag_id
+    assert tag.metric.min == 1.
+    assert tag.metric.max == 10.
+
+    metric = (
+        db.session
+        .query(model.Metric)
+        .filter(model.Metric.tag_id == tag.tag_id)
+        .one())
+    assert metric.min == 1.
+    assert metric.max == 10.
+
+    post_metric = (
+        db.session
+        .query(model.PostMetric)
+        .filter(model.PostMetric.tag_id == tag.tag_id and
+                model.PostMetric.post_id == post.post_id)
+        .one())
+    assert post_metric.value == 5.5
+
+    post_metric_range = (
+        db.session
+        .query(model.PostMetricRange)
+        .filter(model.PostMetricRange.tag_id == tag.tag_id and
+                model.PostMetricRange.post_id == post.post_id)
+        .one())
+    assert post_metric_range.low == 2.
+    assert post_metric_range.high == 8.
+
+    tag = (
+        db.session
+        .query(model.Tag)
+        .filter(model.Tag.tag_id == metric.tag_id)
+        .one())
+    assert tag.metric == metric
+
+
+def test_cascade_delete_metric(post_factory, tag_factory):
+    tag = tag_factory()
+    post1 = post_factory(tags=[tag])
+    post2 = post_factory(tags=[tag])
+    metric = model.Metric(tag=tag, min=1., max=10.)
+    post_metric1 = model.PostMetric(metric=metric, post=post1, value=2.3)
+    post_metric2 = model.PostMetric(metric=metric, post=post2, value=4.5)
+    post_metric_range = model.PostMetricRange(
+        metric=metric, post=post2, low=2, high=8)
+    db.session.add_all([post1, post2, tag, metric, post_metric1, post_metric2,
+                        post_metric_range])
+    db.session.flush()
+
+    assert not db.session.dirty
+    assert db.session.query(model.Post).count() == 2
+    assert db.session.query(model.Tag).count() == 1
+    assert db.session.query(model.Metric).count() == 1
+    assert db.session.query(model.PostMetric).count() == 2
+    assert db.session.query(model.PostMetricRange).count() == 1
+
+    db.session.delete(metric)
+    db.session.commit()
+
+    assert not db.session.dirty
+    assert db.session.query(model.Post).count() == 2
+    assert db.session.query(model.Tag).count() == 1
+    assert db.session.query(model.Metric).count() == 0
+    assert db.session.query(model.PostMetric).count() == 0
+    assert db.session.query(model.PostMetricRange).count() == 0
+
+
+def test_cascade_delete_tag(post_factory, tag_factory):
+    tag1 = tag_factory()
+    tag2 = tag_factory()
+    post = post_factory(tags=[tag1, tag2])
+    metric1 = model.Metric(tag=tag1, min=1., max=10.)
+    metric2 = model.Metric(tag=tag2, min=2., max=20.)
+    post_metric1 = model.PostMetric(metric=metric1, post=post, value=2.3)
+    post_metric2 = model.PostMetric(metric=metric2, post=post, value=4.5)
+    post_metric_range1 = model.PostMetricRange(
+        metric=metric1, post=post, low=2, high=8)
+    post_metric_range2 = model.PostMetricRange(
+        metric=metric2, post=post, low=2, high=8)
+    db.session.add_all([post, tag1, tag2, metric1, metric2, post_metric1,
+                        post_metric2, post_metric_range1, post_metric_range2])
+    db.session.commit()
+
+    assert not db.session.dirty
+    assert db.session.query(model.Post).count() == 1
+    assert db.session.query(model.Tag).count() == 2
+    assert db.session.query(model.Metric).count() == 2
+    assert db.session.query(model.PostMetric).count() == 2
+    assert db.session.query(model.PostMetricRange).count() == 2
+
+    db.session.delete(tag2)
+    db.session.commit()
+
+    assert not db.session.dirty
+    assert db.session.query(model.Post).count() == 1
+    assert db.session.query(model.Tag).count() == 1
+    assert db.session.query(model.Metric).count() == 1
+    assert db.session.query(model.PostMetric).count() == 1
+    assert db.session.query(model.PostMetricRange).count() == 1
+
+
+def test_cascade_delete_post(post_factory, tag_factory):
+    tag = tag_factory()
+    post1 = post_factory(tags=[tag])
+    post2 = post_factory(tags=[tag])
+    metric = model.Metric(tag=tag, min=1., max=10.)
+    post_metric1 = model.PostMetric(metric=metric, post=post1, value=2.3)
+    post_metric2 = model.PostMetric(metric=metric, post=post2, value=4.5)
+    post_metric_range1 = model.PostMetricRange(
+        metric=metric, post=post1, low=2, high=8)
+    post_metric_range2 = model.PostMetricRange(
+        metric=metric, post=post2, low=2, high=8)
+    db.session.add_all([post1, post2, tag, metric, post_metric1, post_metric2,
+                        post_metric_range1, post_metric_range2])
+    db.session.commit()
+
+    assert not db.session.dirty
+    assert db.session.query(model.Post).count() == 2
+    assert db.session.query(model.Tag).count() == 1
+    assert db.session.query(model.Metric).count() == 1
+    assert db.session.query(model.PostMetric).count() == 2
+    assert db.session.query(model.PostMetricRange).count() == 2
+
+    db.session.delete(post2)
+    db.session.commit()
+
+    assert not db.session.dirty
+    assert db.session.query(model.Post).count() == 1
+    assert db.session.query(model.Tag).count() == 1
+    assert db.session.query(model.Metric).count() == 1
+    assert db.session.query(model.PostMetric).count() == 1
+    assert db.session.query(model.PostMetricRange).count() == 1
+
+
+def test_delete_post_metric_no_cascade(
+        post_factory, tag_factory, metric_factory,
+        post_metric_factory, post_metric_range_factory):
+    tag = tag_factory()
+    post = post_factory(tags=[tag])
+    metric = metric_factory(tag=tag)
+    post_metric = post_metric_factory(post=post, metric=metric)
+    post_metric_range = post_metric_range_factory(post=post, metric=metric)
+    db.session.add(metric)
+    db.session.commit()
+    assert len(metric.post_metrics) == 1
+
+    db.session.delete(post_metric)
+    db.session.delete(post_metric_range)
+    db.session.commit()
+    assert len(metric.post_metrics) == 0
+    assert len(metric.post_metric_ranges) == 0
+
+
+def test_tag_without_metric(tag_factory):
+    tag = tag_factory(names=['mytag'])
+    assert tag.metric is None
+    db.session.add(tag)
+    db.session.commit()
+    tag = (
+        db.session
+        .query(model.Tag)
+        .join(model.TagName)
+        .filter(model.TagName.name == 'mytag')
+        .one())
+    assert tag.metric is None
+
+
+def test_metric_counts(post_factory, metric_factory):
+    metric = metric_factory()
+    post1 = post_factory(tags=[metric.tag])
+    post2 = post_factory(tags=[metric.tag])
+    post_metric1 = model.PostMetric(post=post1, metric=metric, value=1.2)
+    post_metric2 = model.PostMetric(post=post2, metric=metric, value=3.4)
+    post_metric_range = model.PostMetricRange(post=post1, metric=metric, low=5.6, high=7.8)
+    db.session.add_all([metric, post_metric1, post_metric2, post_metric_range])
+    db.session.flush()
+    assert metric.post_metric_count == 2
+    assert metric.post_metric_range_count == 1
+
+
+def test_cascade_on_remove_tag_from_post(
+        post_factory, tag_factory, metric_factory,
+        post_metric_factory, post_metric_range_factory):
+    tag = tag_factory()
+    post = post_factory(tags=[tag])
+    metric = metric_factory(tag=tag)
+    post_metric = post_metric_factory(post=post, metric=metric)
+    post_metric_range = post_metric_range_factory(post=post, metric=metric)
+    db.session.add_all([post, tag, metric, post_metric, post_metric_range])
+    db.session.commit()
+
+    assert not db.session.dirty
+    assert db.session.query(model.Post).count() == 1
+    assert db.session.query(model.Tag).count() == 1
+    assert db.session.query(model.PostTag).count() == 1
+    assert db.session.query(model.Metric).count() == 1
+    assert db.session.query(model.PostMetric).count() == 1
+    assert db.session.query(model.PostMetricRange).count() == 1
+
+    post.tags.clear()
+    db.session.commit()
+
+    assert not db.session.dirty
+    assert db.session.query(model.Post).count() == 1
+    assert db.session.query(model.Tag).count() == 1
+    assert db.session.query(model.PostTag).count() == 0
+    assert db.session.query(model.Metric).count() == 1
+    assert db.session.query(model.PostMetric).count() == 0
+    assert db.session.query(model.PostMetricRange).count() == 0
diff --git a/server/szurubooru/tests/search/configs/test_post_metric_search_config.py b/server/szurubooru/tests/search/configs/test_post_metric_search_config.py
new file mode 100644
index 00000000..4eba809b
--- /dev/null
+++ b/server/szurubooru/tests/search/configs/test_post_metric_search_config.py
@@ -0,0 +1,89 @@
+import pytest
+from szurubooru import db, model, errors, search
+
+
+@pytest.fixture
+def executor():
+    return search.Executor(search.configs.PostMetricSearchConfig())
+
+
+@pytest.fixture
+def verify_unpaged(executor):
+    def verify(input, expected_values):
+        actual_count, actual_post_metrics = executor.execute(
+            input, offset=0, limit=100)
+        actual_values = ['%s:%r' % (u.metric.tag_name, u.value)
+                         for u in actual_post_metrics]
+        assert actual_count == len(expected_values)
+        assert actual_values == expected_values
+    return verify
+
+
+def test_refresh_metrics(tag_factory, metric_factory):
+    tag1 = tag_factory(names=['tag1'])
+    tag2 = tag_factory(names=['tag2'])
+    metric1 = metric_factory(tag1)
+    metric2 = metric_factory(tag2)
+    db.session.add_all([tag1, tag2, metric1, metric2])
+    db.session.flush()
+
+    config = search.configs.PostMetricSearchConfig()
+    config.refresh_metrics()
+
+    assert config.all_metric_names == ['tag1', 'tag2']
+
+
+@pytest.mark.parametrize('input,expected_tag_names', [
+    ('', ['t1:10', 't2:20.5', 't1:30', 't2:40']),
+    ('*', ['t1:10', 't2:20.5', 't1:30', 't2:40']),
+    ('t1', ['t1:10', 't1:30']),
+    ('t2', ['t2:20.5', 't2:40']),
+    ('t*', ['t1:10', 't2:20.5', 't1:30', 't2:40']),
+    ('t1,t2', ['t1:10', 't2:20.5', 't1:30', 't2:40']),
+    ('T1,T2', ['t1:10', 't2:20.5', 't1:30', 't2:40']),
+])
+def test_filter_anonymous(
+        verify_unpaged, input, expected_tag_names,
+        post_factory, tag_factory, metric_factory, post_metric_factory):
+    tag1 = tag_factory(names=['t1'])
+    tag2 = tag_factory(names=['t2'])
+    post1 = post_factory(tags=[tag1, tag2])
+    post2 = post_factory(tags=[tag1, tag2])
+    metric1 = metric_factory(tag1)
+    metric2 = metric_factory(tag2)
+    t1_10 = post_metric_factory(post=post1, metric=metric1, value=10)
+    t1_30 = post_metric_factory(post=post2, metric=metric1, value=30)
+    t2_20 = post_metric_factory(post=post1, metric=metric2, value=20.5)
+    t2_40 = post_metric_factory(post=post2, metric=metric2, value=40)
+    db.session.add_all([tag1, tag2, metric1, metric2,
+                        t1_10, t1_30, t2_20, t2_40])
+    db.session.flush()
+    verify_unpaged(input, expected_tag_names)
+
+
+@pytest.mark.parametrize('input,expected_tag_names', [
+    ('t:13', []),
+    ('t:10', ['t:10']),
+    ('t:20.5', ['t:20.5']),
+    ('t:18.6..', ['t:20.5', 't:30', 't:40']),
+    ('t-min:18.6', ['t:20.5', 't:30', 't:40']),
+    ('t:..21.4', ['t:10', 't:20.5']),
+    ('t-max:21.4', ['t:10', 't:20.5']),
+    ('t:17..33', ['t:20.5', 't:30']),
+])
+def test_filter_by_value(
+        verify_unpaged, input, expected_tag_names,
+        post_factory, tag_factory, metric_factory, post_metric_factory):
+    tag = tag_factory(names=['t'])
+    post1 = post_factory(tags=[tag])
+    post2 = post_factory(tags=[tag])
+    post3 = post_factory(tags=[tag])
+    post4 = post_factory(tags=[tag])
+    metric = metric_factory(tag)
+    t1 = post_metric_factory(post=post1, metric=metric, value=10)
+    t2 = post_metric_factory(post=post2, metric=metric, value=30)
+    t3 = post_metric_factory(post=post3, metric=metric, value=20.5)
+    t4 = post_metric_factory(post=post4, metric=metric, value=40)
+    db.session.add_all([tag, metric, t1, t2, t3, t4])
+    db.session.flush()
+    verify_unpaged(input, expected_tag_names)