Free and Open Source Machine Translation API. 100% self-hosted, no limits, no ties to proprietary services. Run your own API server in just a few minutes. Playing with it a little, it seems like it might be interesting to experiment with. Supports a couple of languages right now, but at least they're useful ones.
API docs: https://libretranslate.com/docs/
Language models are kept in a different repo: https://github.com/uav4geo/LibreTranslate-Models
3722 links, including 192 private