HTTP 405 Method Not Allowed vs 510 Not Extended
HTTP 405 (Method Not Allowed) is a 4xx Client Error response, while 510 (Not Extended) is a 5xx Server Error response. 405 indicates that the HTTP method is not allowed for the requested resource. The response includes an Allow header listing valid methods. In contrast, 510 means that further extensions to the request are required for the server to fulfill it.
Description
The HTTP method is not allowed for the requested resource. The response includes an Allow header listing valid methods.
When You See It
When sending POST to a read-only endpoint, or DELETE to a non-deletable resource.
How to Fix
Check the Allow response header for supported methods. Use the correct HTTP method.
Description
Further extensions to the request are required for the server to fulfill it.
When You See It
When an HTTP extension required by the server is not present in the request.
How to Fix
Add the required extension headers to your request.
Key Differences
405 is a 4xx Client Error response, while 510 is a 5xx Server Error response.
HTTP 405: The HTTP method is not allowed for the requested resource. The response includes an Allow header listing valid methods.
HTTP 510: Further extensions to the request are required for the server to fulfill it.
You encounter 405 when when sending POST to a read-only endpoint, or DELETE to a non-deletable resource.
You encounter 510 when when an HTTP extension required by the server is not present in the request.
When to Use Which
For 405 (Method Not Allowed): Check the Allow response header for supported methods. Use the correct HTTP method. For 510 (Not Extended): Add the required extension headers to your request.