mynify

MP4 to WebM. Built for the web.

Convert MP4 videos to efficient WebM for websites — on your device, never uploaded.

  • Never uploaded
  • No limits
  • No signup
  • Free forever

MP4 to WebM, in your browser

WebM is an open, royalty-free video format built for the web. If you’re publishing HTML5 video, prefer an open format, or a tool specifically wants WebM, converting your MP4 is the answer. Mynify does it entirely in your browser, so your video is never uploaded.

What to expect

Converting to WebM re-encodes the video with VP9 and Opus audio. That’s more compute-intensive than MP4, so:

Need the reverse for wider compatibility? WebM to MP4 plays everywhere. Free, unlimited, no signup, no watermark — your video never leaves your device.

Frequently asked questions

Why convert MP4 to WebM?

WebM (VP9) is an open, royalty-free format that's efficient for web video and preferred by some sites and tools. It's a good choice for HTML5 video where an open format matters.

Is my video uploaded?

No — the conversion runs entirely in your browser; your video never leaves your device.

Why does it take a while?

WebM (VP9) re-encoding is compute-intensive and runs on your device, so longer videos take longer. The ~30MB engine also loads once on first use.

Related tools

WebM to MP4 MP4 to MOV Trim / Cut Video