LibreTranslate
Open-source, self-hostable machine translation API (AGPL); run it offline with no key and no quota, or hit a community mirror for free.
LibreTranslate is an AGPL-3.0 MT engine built on the Argos Translate / OpenNMT stack. It exposes a clean REST API (/translate, /detect, /languages, /translate_file) and is designed to be self-hosted via pip or Docker so you own the endpoint with no key, no quota, and no data leaving your infrastructure; it also runs fully offline. The official hosted instance at libretranslate.com now requires an API key, but community mirrors listed in the docs still serve the same API keyless. This is the go-to when an automation needs private, unmetered translation or air-gapped operation.
Free tier
Free and open-source (AGPL-3.0 code; underlying Argos Translate is MIT) when self-hosted; community mirrors are free; the official libretranslate.com hosted service is paid (API key required).Rate limits
Self-hosted: whatever you configure (--req-limit). Community mirrors: not published, intended for light/personal use. Official hosted instance: tiered by purchased key.Auth
No keyBase URL
https://translate.fedilab.appWhat you'd build with it
- Self-host a private, unmetered translation API for an automation
- Offline / air-gapped translation where no data may leave the network
- Language detection (/detect) as a routing step before further processing
- Translate uploaded documents via /translate_file
Key endpoints
- POST
/translateTranslate text; JSON body q, source (or 'auto'), target, format. - POST
/detectDetect the language of a text; JSON body q. Returns ranked confidence scores. - GET
/languagesList supported language codes and their available target languages. - POST
/translate_fileTranslate an uploaded document (multipart form: file, source, target).
Members get the runnable recipe
Sign in free to copy the example request, see a sample response, and read the gotchas.