Voxylio

Voxylio is a browser extension that dubs subtitled videos in real time into French, Spanish, Italian, German or Portuguese. It came out of a simple frustration: following an English video course in your own language, the way YouTube auto-dubbing does, but on any site.

The content script locates the player — including the ones buried in a shadow DOM, like Mux — reads its subtitle track, and rebuilds full sentences out of the caption fragments. Each sentence is translated, preferably by Chrome's on-device translation API, then spoken by a synthesized voice in sync with playback while the original audio ducks underneath.

A pnpm workspace where the dubbing engine is platform-agnostic and each browser is an adapter: Chrome, Edge and Firefox all build from the same core, which is covered by unit tests and Playwright integration runs against the real bundle.