Transmute is a free, open-source, self-hosted file conversion and compression tool built for privacy and automation. Convert images, video, audio, documents, spreadsheets, subtitles, and fonts entirely locally, or compress supported files to make them smaller without sending anything to a third party. Deploy in seconds with Docker, with no file size limits, no watermarks, and no external access to your files.
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Note
**This project is human-led and maintainer-reviewed.**
AI tools assist during development (autocomplete, some boilerplate, help with tests) but all code is intentionally written, reviewed, and validated by a human who understands and takes responsibility for the result. This is not an autonomously generated project, and fully AI-generated or agent-submitted contributions are not accepted. See the contributing guide for more details
Built-in authentication: User accounts, role-based access, and API key support out of the box
Docker ready: Deploy with a single command, no complex setup required
REST API: Automate and integrate file conversions via the built-in OpenAPI-documented API
Multiple themes: Seven built-in light and dark UI themes
Warning
**Think carefully before exposing Transmute to the public internet / WAN.**
Transmute includes built-in authentication and per-user data isolation, but is designed for trusted networks. If you expose it beyond your LAN, place it behind a reverse proxy with TLS and rate limiting. The maintainers are not responsible for security issues arising from your deployment configuration.
Transmute supports conversion across a wide range of file types, including images, video, audio, documents, structured data and spreadsheets, subtitles, fonts, and diagrams. The full list of supported formats and conversion pairs is maintained at transmute.sh/conversions
