HTTP

HTTP 103 Early Hints vs 499 Client Closed Request

HTTP 103 (Early Hints) is a 1xx Informational response, while 499 (Client Closed Request) 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, 499 means that a non-standard status code used by Nginx when the client closes the connection before the server responds.

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

A non-standard status code used by Nginx when the client closes the connection before the server responds.

When You See It

In Nginx logs when clients timeout or navigate away before receiving the response.

How to Fix

Optimize server response times. Check for slow upstream services.

Key Differences

1.

103 is a 1xx Informational response, while 499 is a 4xx Client 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 499: A non-standard status code used by Nginx when the client closes the connection before the server responds.

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 499 when in Nginx logs when clients timeout or navigate away before receiving the response.

When to Use Which

For 103 (Early Hints): No fix needed. This optimization helps speed up page loading. For 499 (Client Closed Request): Optimize server response times. Check for slow upstream services.

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