diff --git a/.githooks/pre-commit b/.githooks/pre-commit
new file mode 100755
index 00000000..15eff2aa
--- /dev/null
+++ b/.githooks/pre-commit
@@ -0,0 +1,13 @@
+#!/bin/sh
+
+set -eu
+
+if git diff --cached --quiet -- 'public/locales/*/translations.json'; then
+  exit 0
+fi
+
+snapshot_dir=$(mktemp -d)
+trap 'rm -rf "$snapshot_dir"' EXIT
+
+node scripts/git-staged-snapshot.mjs "$(pwd)" "$snapshot_dir"
+pnpm run check:i18n -- --root="$snapshot_dir" --base-ref=HEAD --staged
diff --git a/.githooks/pre-push b/.githooks/pre-push
new file mode 100755
index 00000000..4e555e81
--- /dev/null
+++ b/.githooks/pre-push
@@ -0,0 +1,24 @@
+#!/bin/sh
+
+set -eu
+
+locale_changed=0
+base_ref=''
+while read -r local_ref local_oid remote_ref remote_oid; do
+  if [ "$local_oid" = "0000000000000000000000000000000000000000" ]; then
+    continue
+  fi
+  if [ "$remote_oid" = "0000000000000000000000000000000000000000" ]; then
+    if git diff-tree --no-commit-id --name-only -r "$local_oid" -- 'public/locales/*/translations.json' | grep -q .; then
+      locale_changed=1
+      base_ref=$(git merge-base "$local_oid" origin/main 2>/dev/null || git rev-parse "$local_oid^")
+    fi
+  elif ! git diff --quiet "$remote_oid..$local_oid" -- 'public/locales/*/translations.json'; then
+    locale_changed=1
+    base_ref=$remote_oid
+  fi
+done
+
+if [ "$locale_changed" -eq 1 ]; then
+  pnpm run check:i18n -- --base-ref="$base_ref"
+fi
diff --git a/.github/workflows/translation-consistency.yml b/.github/workflows/translation-consistency.yml
new file mode 100644
index 00000000..b814fcaf
--- /dev/null
+++ b/.github/workflows/translation-consistency.yml
@@ -0,0 +1,20 @@
+name: Translation consistency
+
+on:
+  push:
+  pull_request:
+
+jobs:
+  check:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: pnpm/action-setup@v4
+        with:
+          version: 10.33.0
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 22
+          cache: pnpm
+      - run: pnpm install --frozen-lockfile
+      - run: pnpm run check:i18n -- --all
diff --git a/package.json b/package.json
index 720745ee..a2ecc9c7 100644
--- a/package.json
+++ b/package.json
@@ -4,6 +4,7 @@
   "private": true,
   "packageManager": "pnpm@10.33.0",
   "scripts": {
+    "prepare": "node scripts/install-git-hooks.mjs",
     "dev": "pnpm run predev && next dev",
     "build": "pnpm run prebuild && next build",
     "start": "next start",
@@ -12,6 +13,7 @@
     "e2e:mock-api": "ts-node --project ./tsconfig.node.json ./tests/e2e/mock-api.ts",
     "lint": "eslint .",
     "lint-fix": "eslint . --fix",
+    "check:i18n": "node ./scripts/check-translations.mjs",
     "predev": "ts-node --project ./tsconfig.node.json ./scripts/prebuild.tsx",
     "prebuild": "cross-env NODE_ENV=production ts-node --project ./tsconfig.node.json ./scripts/prebuild.tsx"
   },
diff --git a/scripts/check-translations.mjs b/scripts/check-translations.mjs
new file mode 100755
index 00000000..9fb0b89c
--- /dev/null
+++ b/scripts/check-translations.mjs
@@ -0,0 +1,190 @@
+#!/usr/bin/env node
+
+import { execFileSync } from 'node:child_process';
+import { existsSync, readdirSync, readFileSync, statSync } from 'node:fs';
+import path from 'node:path';
+import process from 'node:process';
+import { fileURLToPath } from 'node:url';
+
+const REFERENCE_LOCALE = 'en-US';
+
+function flattenKeys(value, prefix = '', keys = new Set()) {
+  if (!value || typeof value !== 'object' || Array.isArray(value)) {
+    keys.add(prefix);
+    return keys;
+  }
+  for (const [key, child] of Object.entries(value)) {
+    flattenKeys(child, prefix ? `${prefix}.${key}` : key, keys);
+  }
+  return keys;
+}
+
+function readTranslation(filePath) {
+  try {
+    return flattenKeys(JSON.parse(readFileSync(filePath, 'utf8')));
+  } catch (error) {
+    throw new Error(`${filePath} is not valid JSON: ${error.message}`);
+  }
+}
+
+function changedFiles(baseRef, root, staged) {
+  if (!baseRef) return [];
+  try {
+    const diffArgs = staged ? ['diff', '--cached', '--name-only', baseRef] : ['diff', '--name-only', baseRef];
+    return execFileSync('git', [...diffArgs, '--', 'public/locales/*/translations.json'], {
+      cwd: root,
+      encoding: 'utf8',
+    })
+      .trim()
+      .split('\n')
+      .filter(Boolean);
+  } catch (error) {
+    throw new Error(`Unable to inspect translation changes against ${baseRef}: ${error.message}`);
+  }
+}
+
+function diffKeys(referenceKeys, localeKeys) {
+  return {
+    missing: [...referenceKeys].filter((key) => !localeKeys.has(key)).sort(),
+    extra: [...localeKeys].filter((key) => !referenceKeys.has(key)).sort(),
+  };
+}
+
+export function runCheck(root = process.cwd(), baseRef, staged = false, repoRoot = process.cwd(), allLocales = false) {
+  const localesRoot = path.join(root, 'public/locales');
+  const errors = [];
+
+  if (!existsSync(localesRoot) || !statSync(localesRoot).isDirectory()) {
+    return ['public/locales directory does not exist.'];
+  }
+
+  const localeDirs = readdirSync(localesRoot)
+    .filter((entry) => statSync(path.join(localesRoot, entry)).isDirectory())
+    .sort();
+
+  if (!localeDirs.includes(REFERENCE_LOCALE)) {
+    errors.push(`Reference locale "${REFERENCE_LOCALE}" is missing from public/locales.`);
+    return errors;
+  }
+
+  const referencePath = path.join(localesRoot, REFERENCE_LOCALE, 'translations.json');
+  if (!existsSync(referencePath)) {
+    errors.push(`${referencePath} is missing.`);
+    return errors;
+  }
+
+  try {
+    readTranslation(referencePath);
+  } catch (error) {
+    errors.push(error.message);
+    return errors;
+  }
+
+  const localeKeysByName = new Map();
+  for (const locale of localeDirs) {
+    const filePath = path.join(localesRoot, locale, 'translations.json');
+    if (!existsSync(filePath)) {
+      errors.push(`${filePath} is missing.`);
+      continue;
+    }
+
+    let localeKeys;
+    try {
+      localeKeys = readTranslation(filePath);
+    } catch (error) {
+      errors.push(error.message);
+      continue;
+    }
+    localeKeysByName.set(locale, localeKeys);
+  }
+
+  if (allLocales) {
+    console.log(`✅ ${REFERENCE_LOCALE} is the reference locale.`);
+    const referenceKeys = localeKeysByName.get(REFERENCE_LOCALE);
+    if (referenceKeys) {
+      for (const locale of localeDirs) {
+        if (locale === REFERENCE_LOCALE) continue;
+        const localeKeys = localeKeysByName.get(locale);
+        if (!localeKeys) {
+          console.log(`❌ ${locale} could not be checked because translations.json is missing or invalid.`);
+          continue;
+        }
+        const { missing, extra } = diffKeys(referenceKeys, localeKeys);
+        if (missing.length === 0 && extra.length === 0) {
+          console.log(`✅ ${locale} matches ${REFERENCE_LOCALE}.`);
+          continue;
+        }
+        console.log(`❌ ${locale} does not match ${REFERENCE_LOCALE}.`);
+        if (missing.length > 0) {
+          errors.push(`public/locales/${locale}/translations.json is missing ${missing.length} key(s) from ${REFERENCE_LOCALE}:\n  ${missing.join('\n  ')}`);
+        }
+        if (extra.length > 0) {
+          errors.push(`public/locales/${locale}/translations.json has ${extra.length} key(s) not present in ${REFERENCE_LOCALE}:\n  ${extra.join('\n  ')}`);
+        }
+      }
+    }
+  }
+
+  if (baseRef && !allLocales) {
+    let files;
+    try {
+      files = changedFiles(baseRef, repoRoot, staged);
+    } catch (error) {
+      errors.push(error.message);
+      return errors;
+    }
+
+    for (const relativePath of files) {
+      const locale = relativePath.split('/')[2];
+      if (locale === REFERENCE_LOCALE) continue;
+
+      const filePath = path.join(root, relativePath);
+      const newKeys = existsSync(filePath) ? readTranslation(filePath) : new Set();
+      const referenceKeys = localeKeysByName.get(REFERENCE_LOCALE);
+      if (!referenceKeys) continue;
+      const { missing, extra } = diffKeys(referenceKeys, newKeys);
+
+      if (missing.length > 0) {
+        errors.push(`${relativePath} is missing ${missing.length} key(s) from ${REFERENCE_LOCALE}:\n  ${missing.join('\n  ')}`);
+      }
+      if (extra.length > 0) {
+        errors.push(`${relativePath} has ${extra.length} key(s) not present in ${REFERENCE_LOCALE}:\n  ${extra.join('\n  ')}`);
+      }
+    }
+  }
+
+  return errors;
+}
+
+function main() {
+  const rootArg = process.argv.find((arg) => arg.startsWith('--root='));
+  const baseRefArg = process.argv.find((arg) => arg.startsWith('--base-ref='));
+  const staged = process.argv.includes('--staged');
+  const allLocales = process.argv.includes('--all');
+  const repoRoot = process.cwd();
+  const root = rootArg ? path.resolve(rootArg.slice('--root='.length)) : process.cwd();
+  const baseRef = baseRefArg?.slice('--base-ref='.length) || resolveDefaultBaseRef(repoRoot);
+  const errors = runCheck(root, baseRef, staged, repoRoot, allLocales);
+
+  if (errors.length > 0) {
+    console.error('Translation consistency check failed.');
+    for (const error of errors) console.error(`\n${error}`);
+    process.exitCode = 1;
+    return;
+  }
+  console.log(`Translation consistency check passed for ${REFERENCE_LOCALE} and all locale files.`);
+}
+
+function resolveDefaultBaseRef(root) {
+  for (const candidate of ['origin/main', 'HEAD^']) {
+    try {
+      return execFileSync('git', ['rev-parse', '--verify', candidate], { cwd: root, encoding: 'utf8' }).trim();
+    } catch {
+      // Try the next available base.
+    }
+  }
+  return undefined;
+}
+
+const scriptPath = process.argv[1] && path.resolve(process.argv[1]);
+if (scriptPath === path.resolve(fileURLToPath(import.meta.url))) main();
diff --git a/scripts/git-staged-snapshot.mjs b/scripts/git-staged-snapshot.mjs
new file mode 100755
index 00000000..1921529e
--- /dev/null
+++ b/scripts/git-staged-snapshot.mjs
@@ -0,0 +1,19 @@
+#!/usr/bin/env node
+
+import { execFileSync } from 'node:child_process';
+import { mkdirSync } from 'node:fs';
+import path from 'node:path';
+import process from 'node:process';
+
+const [repoRoot, destination] = process.argv.slice(2);
+if (!repoRoot || !destination) {
+  console.error('Usage: git-staged-snapshot.mjs <repoRoot> <destination>');
+  process.exit(1);
+}
+
+mkdirSync(destination, { recursive: true });
+const prefix = destination.endsWith(path.sep) ? destination : `${destination}${path.sep}`;
+execFileSync('git', ['checkout-index', '-a', '-f', `--prefix=${prefix}`], {
+  cwd: repoRoot,
+  stdio: 'inherit',
+});
diff --git a/scripts/install-git-hooks.mjs b/scripts/install-git-hooks.mjs
new file mode 100755
index 00000000..d89b5f9c
--- /dev/null
+++ b/scripts/install-git-hooks.mjs
@@ -0,0 +1,10 @@
+#!/usr/bin/env node
+
+import { execFileSync } from 'node:child_process';
+
+try {
+  execFileSync('git', ['rev-parse', '--git-dir'], { stdio: 'ignore' });
+  execFileSync('git', ['config', 'core.hooksPath', '.githooks'], { stdio: 'inherit' });
+} catch {
+  // Package installation is also used outside a Git checkout.
+}