415 Unsupported Media Type
The server refuses the request because the body is in a format it does not support.
What it means
HTTP 415 Unsupported Media Type means the Content-Type of the request body is one the server or the target endpoint cannot handle. Where 406 is about what the client will accept back, 415 is about what the client sent up: the server looks at the payload's declared type and rejects it.
When it happens
It happens when an API expecting application/json receives XML or form-encoded data, when an upload's Content-Type is wrong or missing, or when a client posts a media type the endpoint was never built to parse.
How to fix it
- Set the Content-Type header to a format the endpoint supports, such as application/json.
- Encode the body to match the declared Content-Type.
- Check the API documentation for the media types each endpoint accepts.
SEO impact
None for normal pages. It applies to request bodies, which crawlers do not send when fetching content.
Find out which of your URLs return 415
Paste a list of URLs and Sitewell checks the status code of every one at once — free and without signup.
Related codes
The server could not understand the request due to malformed syntax.
401 UnauthorizedAuthentication is required and has failed or not been provided.
402 Payment RequiredA largely reserved code intended for payment-gated access to a resource.
403 ForbiddenThe server understood the request but refuses to authorize it.
404 Not FoundThe server could not find the requested resource.
405 Method Not AllowedThe HTTP method used is not supported for the requested resource.
Related guides
A plain-English primer on HTTP status codes for SEOs: what the 2xx, 3xx, 4xx, and 5xx families mean, which ones affect rankings, and the codes worth knowing.
How to find and fix broken linksA practical walkthrough for finding broken links on your site, working out why each one breaks, and fixing them so visitors and crawlers stop hitting dead ends.