HTTP 103 Early Hints vs 406 Not Acceptable
HTTP 103 (Early Hints) is a 1xx Informational response, while 406 (Not Acceptable) is a 4xx Client 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, 406 means that the server cannot produce a response matching the Accept headers sent by the client.
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 cannot produce a response matching the Accept headers sent by the client.
When You See It
When requesting a content type the server doesn't support (e.g., Accept: application/xml when only JSON is available).
How to Fix
Adjust the Accept header to a format the server supports.
Key Differences
103 is a 1xx Informational response, while 406 is a 4xx Client 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 406: The server cannot produce a response matching the Accept headers sent by the client.
You encounter 103 when when a server wants the browser to start loading CSS/JS before the full response is ready.
You encounter 406 when when requesting a content type the server doesn't support (e.g., Accept: application/xml when only JSON is available).
When to Use Which
For 103 (Early Hints): No fix needed. This optimization helps speed up page loading. For 406 (Not Acceptable): Adjust the Accept header to a format the server supports.