.vtt MIME type

Q: What Content-Type header should a .vtt file be served with?

Content-Type: text/vtt; charset=utf-8. As a text format, include the charset so browsers don't guess the encoding. It compresses well, so let the server apply gzip or Brotli.

WebVTT subtitlestext & code

text/vtt

Captions and subtitles for HTML <track> elements.

MIME type	text/vtt
Extensions	.vtt
Content-Type	text/vtt; charset=utf-8
Compress in transit?	Yes — enable gzip or Brotli

Good to know

Browsers ignore a <track> file served with the wrong type.
Cross-origin caption files need CORS headers and crossorigin on the <video> element.

Serve .vtt files with the right type

The response header to send:

Content-Type: text/vtt; charset=utf-8

Most servers pick the type from the file extension. If yours sends the wrong one, map it explicitly:

nginx (inside the types block in mime.types)

text/vtt vtt;

Apache (.htaccess or server config)

AddType text/vtt .vtt

Express

res.set("Content-Type", "text/vtt; charset=utf-8");

Python

import mimetypes

mimetypes.add_type("text/vtt", ".vtt")

HTML file input

<input type="file" accept=".vtt,text/vtt">

Check it

See what a server sends for a file, and what type a local file really is by its contents:

curl -sI https://example.com/file.vtt | grep -i '^content-type:'
file --mime-type file.vtt

Frequently asked questions

What is the MIME type for .vtt files?

text/vtt.

What Content-Type header should a .vtt file be served with?

Content-Type: text/vtt; charset=utf-8. As a text format, include the charset so browsers don't guess the encoding. It compresses well, so let the server apply gzip or Brotli.

Related types

.mp4 .webm all MIME types →

Headers that go with it: Content-Type · Content-Disposition · X-Content-Type-Options