100% Client-Side

HTTP Header Parser

Free online HTTP header parser. Paste raw HTTP headers and get a structured, readable breakdown of each header field and its value. — runs 100% in your browser, client-side only. No data is sent to any server. Free to use, no account required.

Free Client-Side No Login No Storage
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How to Use the HTTP Header Parser

  1. Paste raw HTTP headers (from curl, dev tools, etc.).
  2. Click Parse to get a structured, numbered breakdown.

Detects HTTP status lines and request lines automatically. Each header is parsed into name-value pairs.

What is HTTP Header Parser?

An HTTP header parser analyzes and explains HTTP request/response headers. It breaks down headers into readable components, explains their purposes, and identifies security headers and their configurations.

Why Use This Tool

HTTP headers control caching, security, content negotiation, and more. Understanding what headers mean helps debug issues, configure servers correctly, and implement security best practices.

When to Use It

Use HTTP header parsing when debugging API responses, auditing security headers, understanding caching behavior, or diagnosing CORS and content-type issues.

Who Should Use It

Backend engineers, API support teams, frontend debuggers, and security reviewers.

How to Use the HTTP Header Parser

  1. Paste raw headers from logs or devtools
  2. Parse and inspect key directives
  3. Focus on CORS, cache, CSP, and auth headers
  4. Update server config and retest

Security note

Redact Authorization, cookies, and session identifiers before sharing parsed headers.

Common Uses

  • Debugging API response headers
  • Auditing security header configuration
  • Diagnosing caching issues

Frequently Asked Questions

What are the most important security headers?

Content-Security-Policy (XSS prevention), Strict-Transport-Security (force HTTPS), X-Frame-Options (clickjacking), X-Content-Type-Options (MIME sniffing).

How do caching headers work?

Cache-Control sets caching rules (max-age, no-cache). ETag/Last-Modified enable conditional requests. Vary specifies which request headers affect caching.

What causes CORS errors?

Missing or incorrect Access-Control-Allow-Origin header. The server must explicitly allow the requesting origin, or use * for public APIs.