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HTTP Headers Parser – Fast Raw Headers to JSON Analyzer

Paste request or response headers to parse, decode, detect duplicates, and highlight CORS/security/auth headers with table and JSON output.

No uploads. Everything runs locally in your browser.

Status

Example loaded. Click Parse to analyze headers.

Total: 0Unique: 0Duplicates: 0Categories: 0
Insights

No insights yet. Parse headers to see highlights.

Parsed headers
No headers parsed yet. Click Parse to see results.
JSON output
No JSON output yet. Parse to generate.

What is this tool

The HTTP Headers Parser converts raw request or response headers into readable tables and JSON. It highlights important auth, CORS, security, and cookie headers, counts duplicates, and gives quick insights for debugging.

Use cases

  • Debug API requests by inspecting request/response headers.
  • Check CORS, auth, and security headers before deployment.
  • Share parsed headers with teammates as JSON or table.
  • Verify duplicate or multi-value headers like Set-Cookie.
  • Quickly understand browser DevTools headers without manual parsing.

Popular ways to use this tool

  • Paste response headers from DevTools to audit CORS and security.
  • Analyze API client requests for missing or duplicate headers.
  • Extract Set-Cookie headers for testing auth/session flows.
  • Convert raw header dumps into JSON for documentation.
  • Use as a reference for parsing headers in Node.js or frontend code.

How to use HTTP Headers Parser

  1. Paste raw HTTP headers (request/response or DevTools copy).
  2. Click Parse to decode and structure headers with categories and counts.
  3. Review table, insights, duplicates, and copy JSON or parsed headers.
  4. Use Fill example or Clear to reset and parse another set.

Key features of HTTP Headers Parser

  • Parses raw HTTP headers with duplicate and empty value support
  • Highlights important headers (auth, CORS, security, cookies)
  • Shows table view, JSON output, and insights summary
  • Counts total, unique, duplicate headers plus detected categories
  • Copy parsed headers or JSON; example fill and clear/reset
  • Client-side only parsing with stable order and no uploads

HTTP Headers Parser — key benefits

  • Completely free with no signup or registration required.
  • Runs entirely in your browser — your data is never uploaded.
  • Works on desktop, tablet, and mobile devices.
  • Instant results with no waiting or processing queues.
  • Part of the ToolCircuit suite of free online developer tools tools.

FAQ

Which headers are highlighted?

Common auth, CORS, and security headers like Authorization, Content-Type, Access-Control-Allow-Origin, Content-Security-Policy, X-Frame-Options, and Set-Cookie are highlighted as important.

Do you handle duplicate headers?

Yes. Duplicate headers are grouped into arrays and surfaced in both the table and JSON outputs.

Can I parse response headers from DevTools?

Yes. Paste raw headers from browser DevTools or any HTTP client; the parser will normalize and decode them.

Is any data uploaded?

No. Parsing runs locally in your browser.

Can I copy the results?

Yes. Copy either the parsed headers (flat) or the JSON output via the provided buttons.

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