audio/mp4 is a audio media type commonly associated with .m4a, .mp4a, .m4b extensions.
Quick facts
What is audio/mp4
audio/mp4 is one of the audio media types used on the internet. When serving this content over HTTP, set the Content-Type header in the response, for example:
Content-Type: audio/mp4
Related entities: associated extensions include .m4a、.mp4a、.m4b, and is delivered over HTTP via the Content-Type header, commonly with GET, POST, PUT and PATCH requests.
Related formats:
Relation chain
Related extensions
Related MIME types
Used with
Related headers
Related methods
Frequently asked questions
audio/mp4 is a audio media type used to identify a content format; servers announce it to clients with the Content-Type header.
Extensions such as .m4a, .mp4a, .m4b are associated with this MIME type.
Send Content-Type: audio/mp4 in the HTTP response.
Sources & standards
Updated 2026-08-18
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