HTTP 103 Early Hints vs 415 Unsupported Media Type
HTTP 103 (Early Hints) is a 1xx Informational response, while 415 (Unsupported Media Type) 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, 415 means that the server refuses to accept the request because the Content-Type is not supported.
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 refuses to accept the request because the Content-Type is not supported.
When You See It
When sending JSON to an endpoint that only accepts XML, or missing the Content-Type header.
How to Fix
Set the correct Content-Type header matching the data format you're sending.
Key Differences
103 is a 1xx Informational response, while 415 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 415: The server refuses to accept the request because the Content-Type is not supported.
You encounter 103 when when a server wants the browser to start loading CSS/JS before the full response is ready.
You encounter 415 when when sending JSON to an endpoint that only accepts XML, or missing the Content-Type header.
When to Use Which
For 103 (Early Hints): No fix needed. This optimization helps speed up page loading. For 415 (Unsupported Media Type): Set the correct Content-Type header matching the data format you're sending.