BYTETOOLS

HTTP Header Parser

Paste raw HTTP request or response headers and get a clean name/value table with explanations, directive breakdowns and duplicate detection. Free and private.

What is the HTTP Header Parser?

The ByteTools HTTP Header Parser turns a raw block of HTTP headers — copied from curl -v, a proxy, browser dev tools or a server log — into a readable table.

  • Parses request lines (GET /path HTTP/1.1) and status lines (HTTP/1.1 200 OK)
  • Folds obsolete continuation lines and trims whitespace correctly
  • Explains 25+ common request and response headers inline
  • Breaks Cache-Control, Content-Type and cookie headers into their directives
  • Flags duplicate header names
  • 100% client-side — safe for headers containing tokens and cookies

How to use the HTTP Header Parser

  1. 1

    Copy raw headers from dev tools, curl -v output or a log file.

  2. 2

    Paste the block into the input, including the request or status line if you have it.

  3. 3

    Click Parse headers.

  4. 4

    Review the start-line summary, the name/value table, directive breakdowns and any duplicate warnings.

About the HTTP Header Parser

The ByteTools HTTP Header Parser turns a raw block of HTTP headers — copied from curl -v, a proxy, browser dev tools or a server log — into a readable table. It recognises the request line or status line, splits every header into name and value, and folds legacy continuation lines correctly.

Common headers get inline explanations, and composite values are broken into their parts: Cache-Control is split into its directives, Content-Type into media type and charset, and CORS headers are flagged so you can spot a misconfigured Access-Control-Allow-Origin at a glance. Duplicate header names are highlighted too.

Parsing happens entirely in your browser — headers often contain cookies and authorization tokens, and none of it is uploaded anywhere.

Frequently asked questions

How do I read raw HTTP headers?

Each line is a name, a colon, and a value — for example Content-Type: application/json. The first line is special: in a request it holds the method, path and protocol version; in a response it holds the version, status code and reason phrase. This parser labels all of those parts for you.

Where do I get raw headers to paste in?

In Chrome or Firefox dev tools, open the Network tab, click a request, and use the Raw toggle or right-click to copy request/response headers. On the command line, curl -v and curl -I print them directly.

What does Cache-Control: max-age=3600, must-revalidate mean?

max-age=3600 lets caches reuse the response for one hour, and must-revalidate requires them to check back with the origin server once it is stale. The parser splits every Cache-Control value into individual directives and explains each one.

Are duplicate headers allowed in HTTP?

Only for headers defined as comma-separable lists, like Accept or Via — and Set-Cookie, which is a special case that may appear many times. A duplicated Content-Type or Content-Length usually signals a bug or a smuggling risk, so the parser flags every repeated name.

Is it safe to paste headers containing an Authorization token?

Yes. Parsing is done entirely in your browser tab and nothing is transmitted, logged or stored. Still, treat pasted tokens as sensitive — clear the input when you are done on a shared machine.

Does this tool fetch headers from a URL?

No. It analyses header text you already have. Fetching live headers from an arbitrary site needs a server-side request, which this fully offline tool deliberately avoids — that is what keeps your data private.

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