The DevOps Drop
Home / Encyclopedia / HTTP Status Codes / 4xx Client Error Responses / 431 Request Header Fields Too Large

431 Request Header Fields Too Large

The HTTP 431 Request Header Fields Too Large status code indicates that request headers exceed the server limits.

Published 16 Jul 2026 · HTTP Status Code

What is HTTP 431 Request Header Fields Too Large?

The 431 Request Header Fields Too Large response occurs when headers are too large to process.

Common Causes

  • Large cookies
  • Oversized authentication headers
  • Incorrect proxy configuration

Summary

431 Request Header Fields Too Large means request headers exceed allowed limits.