Josh Liljenquist

Private, browser-local utility

HTTP Header Parser

Parse raw HTTP request, response, or header-only text locally without contacting any host.

Inputs and results stay in this browser tab. Nothing is uploaded, fetched, or stored.

Authorization, Proxy-Authorization, Cookie, and Set-Cookie values are masked by default.

Loading local tool…

RFC 9110 parsing boundary

V1 detects a conventional request line, response status line, or header-only block and preserves duplicate fields as separate records. It accepts CRLF or LF delimiters, trims optional whitespace around values, rejects malformed field names and obsolete folded lines, and limits input to 100,000 characters and 1,000 lines.

This parser performs no DNS lookup, fetch, URL inspection, or remote header request. Revealing a masked value is deliberate, temporary, and local.