i18nGPT translates a project’s locale files, the JSON files that hold every piece of translatable text in an app or website, by sending them through an AI model rather than a plain machine-translation API, aiming for translations that read more naturally and hold up better across a large file. It includes a web-based editor for reviewing and adjusting translations before exporting, can export multiple locale files at once, and splits large JSON files into smaller chunks so the underlying model does not break the file’s structure partway through. It is an open-source project, with more than 800 stars and nearly 100 forks on GitHub, built by a single developer credited as ObservedObserver, who created it after finding Google Translate too limited and raw ChatGPT prone to breaking large JSON files.
i18nGPT is a self-hosted, open-source tool rather than a maintained commercial service: running it requires your own OpenAI API key and, for anything beyond the public demo, your own deployment. The project’s own documentation states its public demo can run slow and sometimes hits Vercel’s serverless function limits, an issue the developer describes as still being worked on, so a team with a real production localization workload should expect to self-host it rather than depend on the shared demo.
The tool itself is free and open-source under an AGPL-3.0 license; using it costs only whatever OpenAI API usage a person’s own API key consumes, with no separate subscription or license fee to the developer.
