HTTP 431 Request Header Fields Too Large vs 504 Gateway Timeout
HTTP 431 (Request Header Fields Too Large) is a 4xx Client Error response, while 504 (Gateway Timeout) is a 5xx Server Error response. 431 indicates that the server refuses to process the request because an individual header field or all headers collectively are too large. In contrast, 504 means that the server, acting as a gateway or proxy, did not receive a timely response from the upstream server.
Description
The server refuses to process the request because an individual header field or all headers collectively are too large.
When You See It
When cookies accumulate to an excessive size, or a single header (like Authorization) is too long.
How to Fix
Reduce header sizes. Clear excessive cookies. Use shorter tokens.
Description
The server, acting as a gateway or proxy, did not receive a timely response from the upstream server.
When You See It
When an upstream server is too slow to respond within the proxy's timeout window.
How to Fix
Increase proxy timeout settings. Optimize upstream server performance. Check for long-running queries.
Key Differences
431 is a 4xx Client Error response, while 504 is a 5xx Server Error response.
HTTP 431: The server refuses to process the request because an individual header field or all headers collectively are too large.
HTTP 504: The server, acting as a gateway or proxy, did not receive a timely response from the upstream server.
You encounter 431 when when cookies accumulate to an excessive size, or a single header (like Authorization) is too long.
You encounter 504 when when an upstream server is too slow to respond within the proxy's timeout window.
When to Use Which
For 431 (Request Header Fields Too Large): Reduce header sizes. Clear excessive cookies. Use shorter tokens. For 504 (Gateway Timeout): Increase proxy timeout settings. Optimize upstream server performance. Check for long-running queries.