HTTP Headers Analyzer
Parse and explain raw HTTP response headers.
Processed locally in your browser. Nothing you enter is uploaded or stored.
- Explains each recognised header inline — caching, CORS, security, content negotiation.
- Works on headers you paste, so it's usable for any site or environment.
- Runs in your browser; headers aren't uploaded.
Why this is private
- Processed locally in your browser. Nothing you enter is uploaded or stored.
- Open your browser's DevTools → Network tab while using this tool — you won't see a request carrying your input, because it never leaves your device.
- Nothing you enter is uploaded to a server or shared with us — the processing happens entirely on your device.
Overview
Parses raw HTTP response headers and explains what each common one does — useful for debugging caching, CORS or security header issues.
How to use it
- 1Paste raw response headers, one per line (as shown by your browser's network tab).
- 2Each recognized header is explained below it.
Tips
- This explains headers you paste in — it doesn't fetch a live URL, since cross-origin header inspection from a browser is blocked by CORS for most sites.
Frequently asked questions
What people use it for
Debug why a resource isn't cachedRead `Cache-Control`, `ETag` and `Expires` to see what the browser will do.
Track down a CORS failureCheck `Access-Control-Allow-Origin` and friends against what the request needs.
Audit security headersSee whether `Strict-Transport-Security`, `X-Content-Type-Options` and CSP are present.
Understand a redirect or content typeInspect `Location`, `Content-Type` and `Content-Disposition` on a response.
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HTTP Headers Analyzer