HTTP 308 Permanent Redirect vs 501 Not Implemented
HTTP 308 (Permanent Redirect) is a 3xx Redirection response, while 501 (Not Implemented) is a 5xx Server Error response. 308 indicates that the resource has been permanently moved. Like 301, but guarantees the HTTP method will NOT be changed. In contrast, 501 means that the server does not support the functionality required to fulfill the request. The server either does not recognize the request method or lacks the ability to fulfill it.
Description
The resource has been permanently moved. Like 301, but guarantees the HTTP method will NOT be changed.
When You See It
For permanent URL changes where POST requests must remain POST.
How to Fix
Update all references to the new URL. The HTTP method is preserved.
Description
The server does not support the functionality required to fulfill the request. The server either does not recognize the request method or lacks the ability to fulfill it.
When You See It
When using an HTTP method (like PATCH) that the server doesn't support.
How to Fix
Use a different HTTP method that the server supports. Check server documentation.
Key Differences
308 is a 3xx Redirection response, while 501 is a 5xx Server Error response.
HTTP 308: The resource has been permanently moved. Like 301, but guarantees the HTTP method will NOT be changed.
HTTP 501: The server does not support the functionality required to fulfill the request. The server either does not recognize the request method or lacks the ability to fulfill it.
You encounter 308 when for permanent URL changes where POST requests must remain POST.
You encounter 501 when when using an HTTP method (like PATCH) that the server doesn't support.
When to Use Which
For 308 (Permanent Redirect): Update all references to the new URL. The HTTP method is preserved. For 501 (Not Implemented): Use a different HTTP method that the server supports. Check server documentation.