HTTP Message Parser — Request, response, headers
Paste a raw HTTP/1.1 request, response, or header block and read the start-line, duplicate headers, and JSON body. HTTP header parser in your browser — nothing is sent or executed.
Developer notes
• RFC 9112 start-line: request, response (e.g. HTTP/1.1 200), or headers-only. • LF and CRLF both accepted. Duplicate headers stay as separate rows (Set-Cookie). • curl -v chatter is ignored when the start-line is cheap to find. • JSON bodies can be pretty-printed inline; validate/repair stays on JSON Formatter / JSON Validator. • No chunked reassembly, no HTTP/2 frames, no request execution.
Options
When this is the right tool
• Read a captured HTTP/1.1 200 and pretty-print the JSON body. • Keep both Set-Cookie lines instead of collapsing them. • Parse a header block without a start-line.
Worked examples
HTTP/1.1 200 + JSON body
Before
After
Duplicate Set-Cookie
Before
After
Related HTTP and JSON tools
Hub: HTTP Tools. Format the JSON body in JSON Formatter or check it with JSON Validator. Tokens: JWT Decode. Specs: API & schema tools.
HTTP Message Parser FAQ
Request, response, headers — local only
Is this an HTTP header parser?
Yes — headers-only blocks work. The same engine also parses full requests and responses. There is no separate headers-only slug.
Are duplicate headers kept?
Yes. Each line is a row, including multiple Set-Cookie headers.
Does pretty-print validate JSON?
No. The toggle only changes display. Use JSON Validator to check or repair JSON.
Does this send the message?
No. FastMinify never executes the request. There is no Send control.
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