Tools

Lingo.dev's official CLI: lingo push sends JSON, YAML, Markdown, PO, XLIFF, Android/Xcode strings and other files from your repo to its LLM localization engine, and lingo pull brings translations back; CI-ready. Needs a Lingo.dev account; usage-based pricing with a free sandbox.

Pluggable natural-language linter that checks Markdown and plain text for wording, punctuation and terminology consistency like code, with auto-fix, and can also run as an MCP server. Rules are installed separately, mostly for Japanese and English; requires Node.js 20+.

Helps app marketers and translators plan multilingual App Store listings: prioritize countries, research keywords per market, rewrite title, subtitle, keywords and description, and flag screenshot and cultural issues rather than translating literally. Guidance only, no account needed.

Translation management for Ruby/Rails: statically analyzes code to find missing and unused keys, normalizes locale files, fills gaps via Google Translate, DeepL or OpenAI, and exports CSV for translators. Requires the i18n gem (Rails default) and Bundler; machine translation needs an API key.

AI localization: deploy the server to your own Vercel account (Postgres and AI Gateway included; enable deployment protection afterwards), then run npx languine@selfhosted translate to translate locale files with LLMs. A GitHub Action can open PRs. Needs a Vercel account and Node.js.

One plugin bundling skills and subagents for deep research, fixing GitHub issues and reviewing PRs, Codex handoff, Gemini or GPT image generation, translation and YouTube transcript extraction, plus settings.json templates for various providers (manual setup). Some skills need API keys.

Sets up and audits i18n for React, Next.js and Vue apps: replaces hard-coded strings with message keys, checks that English and Chinese keys are complete and consistent, and verifies plurals and date and number formats, with a key audit script. Needs a local codebase and Python.

The standard machine translation scorer: computes BLEU, chrF and TER with significance tests and downloads public test sets such as WMT, to compare engines or prompts. Needs Python 3.9+ and reference translations; automatic metrics are a rough screen, so final copy still needs human review.

Community App Store localization skill (not from Apple): uses the asc CLI and an LLM to translate listing copy such as description, keywords, subtitle and release notes into many languages and sync it to App Store Connect. Needs asc set up and authorized; proofread before submitting.

General Translation's gt CLI: a wizard sets up i18n for React, Next.js and similar apps, then sends UI strings and JSON, YAML or Markdown files for AI translation and writes them back, with CI support. Needs a Node.js project and a General Translation API key (free sign-up, usage-based pricing).

Open-source toolkit widely used in localization: converts between PO, XLIFF, TMX, CSV, subtitle and other translation formats, counts words, runs 40+ translation checks with pofilter and extracts frequent terms with poterminology. Needs Python 3.11+.

Microsoft's official skill: has the agent use Microsoft Learn docs to call Azure text and document translation, enforce glossaries, train Custom Translator models and troubleshoot quotas and errors. For localization teams building batch translation; needs an Azure account and Translator resource.

Unbabel's machine-translation quality metric: comet-score rates translations per sentence and overall, XCOMET marks error spans and severity, and CometKiwi works without a reference. Good for spot-checking MT. Needs Python 3.8+; models download from Hugging Face, some need a license; GPU helps.

Official ElevenLabs skills: text to speech, speech to text, sound effects and music generation, voice changing, vocal isolation, multilingual dubbing and building voice agents. Needs an ElevenLabs API key.

Offline translation sync for coding agents: hands only new strings in JSON, YAML, PO, CSV and other locale files to the agent for translation and never overwrites human-edited translations, saving tokens. Needs Node.js; calls no translation API itself.

Crowdin's official CLI: push source files and pull translations back in place, track progress, manage glossaries and TM, and run machine or AI pre-translation, with JSON output for agents. Needs a Crowdin account (free trial; free for open source) and a token; crowdin init sets up config.

i18next's official CLI: finds hard-coded strings in JS/TS code, extracts translation keys, checks which locales are missing entries and syncs locale files; init --yes sets up non-interactively, and a bundled agent skill guides app internationalization. Needs a Node.js project using i18next.

Microsoft Translator's translation quality tool: GPT scores each sentence using MQM error categories or a direct score; --list_mqm_errors shows error types and severity. Needs line-aligned source and target files, Python and an OpenAI or Azure OpenAI key (paid); a translator should still review.

Lokalise's official CLI (lokalise2) covering the Lokalise API v2: upload and download language files and manage keys, translations, screenshots, translation tasks and contributors. Needs a Lokalise account (paid, 14-day free trial) and an API token passed via --token.

SimpleLocalize's official CLI: upload and download translation files, trigger machine and AI auto-translation, publish translations to the CDN, and extract translation keys from source code for CI. Needs a SimpleLocalize account and project API key; paid service with a 14-day free trial.

Locize's official CLI: sync local translation files with the Locize platform, add, remove and look up keys, download published translations, manage versions and branches, and export JSON, XLIFF, PO, CSV or Excel for translators. Needs a Locize account, project ID and API key; free plan available.

Phrase Strings' official CLI: phrase init walks you through config, then phrase push uploads language files and phrase pull fetches the latest translations; it also wraps the full API for projects, locales and keys. Needs a Phrase Strings account (paid, 14-day free trial) and an API token.

Official CLI for Weblate, the open-source translation platform: check translation progress for projects and components, upload and download translation files, lock components, and commit or push repository changes. Hosted or self-hosted; needs the server URL, an API key and Python.

Community MCP for Weblate, the open-source translation platform (self-hosted or hosted): translators can find untranslated or needs-editing strings in plain language, write translations in bulk, and check per-language progress and change history. Needs your Weblate API URL and token, and Node.js.