crowdin.com — Unlimited projects, unlimited strings, and collaborators for Open Source
gitlocalize.com - Free and unlimited for both private and public repositories
Lecto - Machine Translation API with Free tier (30 free requests, 1000 translated characters per request). Integrated with the Loco Translate Wordpress plugin.
lingohub.com — Free up to 3 users, always free for Open Source
localazy.com - Free for 1000 source language strings, unlimited languages, unlimited contributors, startup and open source deals
Localeum - Free up to 1000 strings, one user, unlimited languages, unlimited projects
Lingo.dev – Open-source AI-powered CLI for web & mobile localization. Bring your own LLM, or use 10,000 free words every month via Lingo.dev-managed localization engine.