HTTP

HTTP 103 Early Hints vs 505 HTTP Version Not Supported

HTTP 103 (Early Hints) is a 1xx Informational response, while 505 (HTTP Version Not Supported) 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, 505 means that the server does not support the HTTP version used in the request.

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 HTTP version used in the request.

When You See It

When a client uses an HTTP version the server doesn't support.

How to Fix

Use a supported HTTP version (typically HTTP/1.1 or HTTP/2).

Key Differences

1.

103 is a 1xx Informational response, while 505 is a 5xx Server Error response.

2.

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.

3.

HTTP 505: The server does not support the HTTP version used in the request.

4.

You encounter 103 when when a server wants the browser to start loading CSS/JS before the full response is ready.

5.

You encounter 505 when when a client uses an HTTP version the server doesn't support.

When to Use Which

For 103 (Early Hints): No fix needed. This optimization helps speed up page loading. For 505 (HTTP Version Not Supported): Use a supported HTTP version (typically HTTP/1.1 or HTTP/2).

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