Aarunya AppsAarunya Apps
video/webm

video/webm MIME Type — WebM vs MP4, Browser Support & Examples

WebM is an open, royalty-free video format based on the Matroska container with VP8/VP9/AV1 video and Vorbis/Opus audio. Supported by all modern browsers. Often used alongside MP4 in <source> elements for maximum compatibility.

Type
video
Compressible
No (pre-compressed)
Extensions
.webm

Used For

  • Web video with royalty-free codec (VP9/AV1)
  • Screen recordings
  • Alternative to MP4 for open-source projects

HTTP Header Example

HTTP/1.1 200 OK
Content-Type: video/webm
Accept-Ranges: bytes

Code Examples

// HTML — serve WebM with MP4 fallback
<video controls width="640" height="360">
  <source src="/video.webm" type="video/webm" />
  <source src="/video.mp4" type="video/mp4" />
  Your browser does not support HTML5 video.
</video>

// Express
app.get('/video.webm', (req, res) => {
  res
    .set('Content-Type', 'video/webm')
    .set('Accept-Ranges', 'bytes')
    .sendFile('./videos/video.webm', { root: process.cwd() })
})

Related MIME Types

video/mp4

All MIME Types

Browse the complete MIME type reference.

View All MIME Types

Frequently Asked Questions

What is the video/webm MIME type?

WebM is an open, royalty-free video format based on the Matroska container with VP8/VP9/AV1 video and Vorbis/Opus audio. Supported by all modern browsers. Often used alongside MP4 in <source> elements for maximum compatibility.

When should I set Content-Type: video/webm?

Set Content-Type: video/webm on HTTP responses that contain WebM Video data. Web video with royalty-free codec (VP9/AV1).

What file extensions use video/webm?

Files with video/webm content typically use these extensions: .webm.

What happens if I serve this with the wrong Content-Type?

Browsers use the Content-Type header to decide how to handle the response. Serving video/webm content with an incorrect MIME type can cause browsers to display it incorrectly, refuse to execute it (scripts), or prompt an unintended download. Modern browsers respect X-Content-Type-Options: nosniff and will not attempt to auto-detect the type.