LibreTranslate

Overview

LibreTranslate is an open-source machine-translation API (Argos Translate backend) — a privacy-friendly alternative to Google Translate. The project is designed to be self-hosted: you can run your own instance for free, forever.

⚠️ Status (verified 2026-08): the public instance at libretranslate.com now requires an API key (POST /translate returns 400: Visit https://portal.libretranslate.com to get an API key). The free, unlimited path is self-hosting — which is the project’s intended model anyway.

Quick Start

On a self-hosted instance (or with your portal key):

curl -X POST "http://localhost:5000/translate" \
  -H "Content-Type: application/json" \
  -d '{"q": "Hello world", "source": "en", "target": "es"}'

{"translatedText": "Hola mundo"}

Detect language:

curl -X POST "http://localhost:5000/detect" \
  -H "Content-Type: application/json" \
  -d '{"q": "Hola mundo"}'

List supported languages:

curl "http://localhost:5000/languages"

Authentication

• Public instance: requires a (free) API key from portal.libretranslate.com.
• Self-hosted: no auth by default (add api_keys in the config if you want keys).

Rate Limits & Notes

• The public instance is rate-limited; self-hosting removes limits entirely.
• ~130+ languages; translation quality varies by language pair (Argos models).
• Docker deployment is one command: docker run -p 5000:5000 libretranslate/libretranslate.
• Privacy-friendly: self-hosted means your text never leaves your server.

FAQ

Is LibreTranslate free? The software is free and open-source. The public instance now requires a free key; self-hosting is free forever.

Do I need a key? On the public instance, yes. On your own instance, no (by default).

How do I self-host? docker run -p 5000:5000 libretranslate/libretranslate — then use localhost:5000.