Getting 'Request Header Fields Too Large' Error – How to Fix It? or What Causes 'Request Header Field

Fun fact: This error can pop up if you’re using JWT tokens and they’re massive. Had a client with this exact problem.

Short-term fix? Reduce the payload in your tokens. Long-term? Maybe switch to session IDs or split the token into smaller chunks.

Also, Firefox seems to handle large headers better than Chrome, weirdly.