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Server Error (5xx)

HTTP/1.1

501 Not Implemented

The server does not support the functionality required to fulfill the request.

CategoryServer Error (5xx)
API error types1 error schema
Related headers1 header
Updated2026-07-09

What does HTTP status code 501 mean?

The 501 Not Implemented status code indicates that the server does not support or recognize the request method or capability.

When to use it in APIs

Used when stubbing out new endpoints or when an API does not support certain standard HTTP operations (like a read-only API receiving a DELETE request).

How it compares to other codes

  • 405 Method Not Allowed: Implies the method is recognized by the server but is not permitted on that specific route. 501 implies the server lacks the capacity to perform the method globally.

Problem types for 501

1