HTTP header parser

SEO & Dev publishing

Parse raw HTTP headers into structured key-value entries for debugging.

Updated May 30, 2026

Raw headers

Parsed output

[
  {
    "name": "Content-Type",
    "value": "application/json"
  },
  {
    "name": "Cache-Control",
    "value": "no-cache"
  },
  {
    "name": "X-Request-Id",
    "value": "abc-123"
  }
]

Quick start

How to use http-header-parser

Configure inputs and generate output.

Step 1

Set inputs

Enter required fields.
Step 2

Generate

Create output instantly.
Step 3

Use output

Copy and apply in your workflow.

In-depth guide

Reading HTTP headers: a practical debugging guide

HTTP headers carry the metadata of every request and response — caching rules, authentication, CORS permissions, content type and more. When an API misbehaves, the answer is usually in the headers. This tool turns a raw header block into structured, readable key-value JSON entirely in your browser.

How to use this tool

Copy a raw header block — from browser DevTools, curl -i, or a server log.
Paste it in, one Name: value pair per line.
Read the parsed JSON, or feed it into a script or test assertion.

Headers worth checking first

When debugging, scan for a few high-value headers: Cache-Control and ETag for caching surprises; Content-Type for parsing mismatches; Access-Control-Allow-Origin for CORS failures; Set-Cookie for session issues; and Authorization or WWW-Authenticate for auth problems. Most 4xx mysteries are explained by one of these.

When to use it vs alternatives

This is ideal for quickly making a pasted header dump readable, or normalising headers for a test fixture. For live inspection of traffic, your browser's Network tab or a proxy like mitmproxy will show headers in context as requests happen.

Privacy and a caution

Header dumps often contain cookies, tokens and Authorization values. Treat a pasted block as sensitive and clear it when done.

Parsing happens entirely in your browser — no request is sent and the header text is never uploaded. Even so, avoid pasting production secrets into any tool unless you are comfortable handling them in the current session.

Common pitfalls

Check the result before replacing the original input.
Watch for unit, format, encoding, and browser memory limits on large inputs.
Keep a copy of important source material until the output is verified.

Frequently asked questions

What format does the input accept?

Paste one header per line in Name: value format — exactly as it appears in DevTools, curl -i output or a server log.

Can I parse response headers as well as request headers?

Yes. Any raw header block works the same way, whether it came from a request or a response.

Is parsing done locally?

Yes. Everything runs in your browser — no request is sent and the header text is never uploaded.

Which headers should I check first when debugging?

Start with Cache-Control and ETag for caching, Content-Type for parsing issues, Access-Control-Allow-Origin for CORS, and Authorization or WWW-Authenticate for auth problems.

Can the JSON output feed automated tests?

Yes. The structured key-value JSON is convenient for assertions in tests, monitoring checks and scripts.

Is it safe to paste headers containing tokens?

Parsing is local, but header dumps often contain cookies and Authorization values. Treat them as sensitive and clear them when you are done.

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