HTTP 429 Too Many Requests vs 431 Request Header Fields Too Large
Both HTTP 429 (Too Many Requests) and 431 (Request Header Fields Too Large) belong to the 4xx Client Error category. 429 indicates that the user has sent too many requests in a given time (rate limiting). The response should include a Retry-After header. Meanwhile, 431 means that the server refuses to process the request because an individual header field or all headers collectively are too large.
Description
The user has sent too many requests in a given time (rate limiting). The response should include a Retry-After header.
When You See It
When hitting API rate limits or making too many requests too quickly.
How to Fix
Check the Retry-After header. Implement exponential backoff. Consider caching responses.
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.
Key Differences
HTTP 429: The user has sent too many requests in a given time (rate limiting). The response should include a Retry-After header.
HTTP 431: The server refuses to process the request because an individual header field or all headers collectively are too large.
You encounter 429 when when hitting API rate limits or making too many requests too quickly.
You encounter 431 when when cookies accumulate to an excessive size, or a single header (like Authorization) is too long.
When to Use Which
For 429 (Too Many Requests): Check the Retry-After header. Implement exponential backoff. Consider caching responses. For 431 (Request Header Fields Too Large): Reduce header sizes. Clear excessive cookies. Use shorter tokens.