HTTP 415 Unsupported Media Type — Meaning, Causes & How to Fix
The request body is in a format not supported by the server for this resource.
- Code
- 415
- Name
- Unsupported Media Type
- Class
- 4xx Client Error
- Specification
- RFC 9110 §15.5.16
- Cacheable by default
- Only with explicit Cache-Control / Expires
What HTTP 415 means
415 Unsupported Media Type means the server refuses the request because the body format (its Content-Type or Content-Encoding) is not supported by this endpoint.
Common causes
- Sending JSON without
Content-Type: application/json. - Posting form data to a JSON-only endpoint.
- Uploading a file type the server does not accept.
How to fix it
For site owners
- List accepted types in the error body (or an
Accept-Post/Acceptresponse header).
For visitors & developers
- Set the correct
Content-Typeheader for the body you send.
SEO impact
No SEO impact: it relates to request bodies, not page fetches.
Example 415 response
HTTP/1.1 415 Unsupported Media Type
Accept-Post: application/json
Content-Length: 0Related status codes
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Open HTTP Status Codes tool →All status codesFrequently asked questions
What does HTTP 415 mean?
HTTP 415 Unsupported Media Type is a 4xx Client Error status code. The request body is in a format not supported by the server for this resource.
Why do I get 415 when my JSON is valid?
Usually the Content-Type header is missing or wrong (e.g. text/plain). Set it to application/json.
Which specification defines 415?
It is defined in RFC 9110 §15.5.16.
Is a 415 response cacheable?
Not by default. A 415 response is only stored by caches when it carries explicit freshness information such as Cache-Control: max-age or Expires.