Question 1

Does it explain what each header does?

Accepted Answer

Yes, for the headers most developers actually look at — Cache-Control directives like max-age and no-store, CORS headers like Access-Control-Allow-Origin, the security trio (HSTS, X-Frame-Options, X-Content-Type-Options), and Content-Security-Policy — it shows a short explanation alongside the raw value. Unknown or application-specific headers are listed by name with no commentary.

Question 2

Can I paste request AND response headers?

Accepted Answer

Both. The parser handles the standard key: value format used in either direction; if there is a status line (HTTP/1.1 200 OK) at the top it is recognized as the start of a response, otherwise the block is treated as request-style headers.

Question 3

Can it help me debug a CORS error?

Accepted Answer

Yes — paste the response headers from the failing request and look for the Access-Control-Allow-Origin, Access-Control-Allow-Methods, and Access-Control-Allow-Headers entries. Missing or mismatched values are the usual cause of 'No Access-Control-Allow-Origin header' errors in the browser console.

Question 4

Is anything uploaded?

Accepted Answer

No. Parsing and explanation rendering happen entirely in your browser; the header block is never sent to a server.

HTTP Header Parser

Raw Headers

Parsed

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