Cookie & Header Parser

Parse cookies and HTTP headers to analyze their sizes. Identify oversized items and ensure your requests stay within server limits.

Settings
Configure size limits and display options
bytes (8.00 KB)
Input Mode
Choose how you want to input your data

Format: name=value; name2=value2 or Set-Cookie format with attributes

About HTTP Headers & Cookies
  • Cookie header: Sent by browsers to servers with each request
  • Set-Cookie header: Sent by servers to set cookies in browsers
  • Size limits: Most web servers limit total header size to 8KB-16KB
  • Individual cookie limit: Browsers typically limit each cookie to 4KB
  • Cookie attributes: Domain, Path, Expires/Max-Age, Secure, HttpOnly, SameSite
  • Performance: Larger headers increase request size and latency
  • Common limits: Nginx: 8KB (default), Apache: 8KB, IIS: 16KB