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HTTP Cookie Builder

Build Set-Cookie headers with all standard attributes. Configure name, value, domain, path, expiry, SameSite, Secure, HttpOnly, and Partitioned flags with live validation and security warnings. Runs entirely in your browser — your data never leaves your machine.

http cookie set-cookie security headers web

Published May 30, 2026

All interactive tools run entirely in your browser. Your data never leaves your device.

How It Works

Configure cookie attributes using the form, and the tool generates a valid Set-Cookie header string. It validates names, values, and flags, warning about common security pitfalls.

Features

  • Full attribute support: name, value, domain, path, Max-Age, Expires, SameSite, Secure, HttpOnly, Partitioned
  • Security warnings: detects insecure configurations (missing flags, prefix violations, SameSite=None without Secure)
  • Cookie prefixes: validates __Host- and __Secure- prefix requirements per RFC 6265bis
  • Parse existing headers: paste a Set-Cookie string to populate the form
  • CHIPS support: Partitioned attribute for cross-site embedded contexts
  • 5 examples: session, persistent, cross-site OAuth, subdomain-scoped, partitioned
  • Private: runs entirely in the browser — no data transmitted

Use Cases

  • Building Set-Cookie headers for API responses
  • Validating cookie security attributes before deployment
  • Learning HTTP cookie specifications (RFC 6265)
  • Debugging cross-site cookie issues (SameSite, Partitioned)