HTTP 103 Early Hints vs 501 Not Implemented
HTTP 103 (Early Hints) is a 1xx Informational response, while 501 (Not Implemented) is a 5xx Server Error response. 103 indicates that used to return some response headers before the final HTTP message. Allows the browser to start preloading resources while the server prepares the response. 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
Used to return some response headers before the final HTTP message. Allows the browser to start preloading resources while the server prepares the response.
When You See It
When a server wants the browser to start loading CSS/JS before the full response is ready.
How to Fix
No fix needed. This optimization helps speed up page loading.
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
103 is a 1xx Informational response, while 501 is a 5xx Server Error response.
HTTP 103: Used to return some response headers before the final HTTP message. Allows the browser to start preloading resources while the server prepares the response.
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 103 when when a server wants the browser to start loading CSS/JS before the full response is ready.
You encounter 501 when when using an HTTP method (like PATCH) that the server doesn't support.
When to Use Which
For 103 (Early Hints): No fix needed. This optimization helps speed up page loading. For 501 (Not Implemented): Use a different HTTP method that the server supports. Check server documentation.