What HTTP 415 means
The Content-Type of the request isn’t one the endpoint accepts, such as XML sent to a JSON API, or no Content-Type at all. It is about the format of what you send; 406 is about the format you ask to receive.
How to fix a 415 error
-
Set
Content-Type: application/jsonwhen sending JSON.fetch()doesn’t set it automatically for a string body. - ASP.NET Core and Spring return 415 when the header is missing entirely.
Retrying
No. Fix the request first; sending it again unchanged will get the same response.
Example response
HTTP/1.1 415 Unsupported Media Type
Date: Wed, 21 Oct 2026 10:30:00 GMT
Content-Type: application/jsonHow to return 415
res.status(415).json({ error: 'Unsupported Media Type' });from fastapi import HTTPException
raise HTTPException(status_code=415, detail="Unsupported Media Type")http.Error(w, http.StatusText(http.StatusUnsupportedMediaType), http.StatusUnsupportedMediaType)location /private/ {
return 415;
}Related status codes
- 406 Not Acceptable : The server can’t produce a response in any format listed in the Accept headers.
- 400 Bad Request : The server can’t process the request because it is malformed.
- 422 Unprocessable Content : The request is well-formed, but its contents fail validation.
Other 4xx status codes
400 Bad Request · 401 Unauthorized · 402 Payment Required · 403 Forbidden · 404 Not Found · 405 Method Not Allowed · 406 Not Acceptable · 407 Proxy Authentication Required · 408 Request Timeout · 409 Conflict · 410 Gone · 411 Length Required · 412 Precondition Failed · 413 Content Too Large · 414 URI Too Long · 416 Range Not Satisfiable · 417 Expectation Failed · 418 I’m a Teapot · 421 Misdirected Request · 422 Unprocessable Content · 423 Locked · 424 Failed Dependency · 425 Too Early · 426 Upgrade Required · 428 Precondition Required · 429 Too Many Requests · 431 Request Header Fields Too Large · 444 No Response · 451 Unavailable For Legal Reasons · 499 Client Closed Request
See the full list of HTTP status codes.
Sources
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Frequently asked questions
What does HTTP 415 Unsupported Media Type mean?
HTTP 415 Unsupported Media Type means the server doesn’t accept the request body’s format. The Content-Type of the request isn’t one the endpoint accepts, such as XML sent to a JSON API, or no Content-Type at all. It is about the format of what you send; 406 is about the format you ask to receive.
How do I fix HTTP 415?
Set Content-Type: application/json when sending JSON. fetch() doesn’t set it automatically for a string body. ASP.NET Core and Spring return 415 when the header is missing entirely.