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HTTP Header Parser and Analyzer

Paste raw HTTP headers, get a clean table with per-header meaning, duplicate and security badges, browser-only

  • Runs locally
  • Category Developer & DevOps
  • Best for Formatting, validating, shrinking, or inspecting code-adjacent text.
Paste a header block above to parse it.

What this tool does

Paste the raw HTTP headers from a curl -I run, a browser DevTools "copy headers" dump, or any request or response block, and this parser turns the wall of text into a clean, structured table. It reads the start line first, whether that is a request line like GET /path HTTP/1.1 or a status line like HTTP/1.1 200 OK, then splits every following Name to value pair on the first colon only, so a URL or a date sitting inside the value stays intact. Repeated headers such as Set-Cookie are each kept in order and flagged, folded continuation lines are joined back together, and stray whitespace is trimmed. Common headers carry a one line plain language explanation, and security relevant headers like HSTS, Content-Security-Policy and the CORS family get a small badge so you can spot what protects the response at a glance. Sort by name or original order, filter by keyword, and copy the cleaned block with one click. Everything runs in your browser with no upload, and sensitive headers like Authorization and Cookie are never written into the shareable URL.

Tool details

Input
Text + Numbers
The page exposes text boxes, numeric controls, file pickers, or structured inputs depending on the tool.
Output
Live result + Copy + Download
The result area focuses on usable output, with copy, download, or preview actions when supported.
Privacy
Browser-side processing
The main tool logic does not call an external API, so inputs normally stay in the current tab.
Save / share
Shareable URL state
Key settings are encoded in the URL so another person can reopen the same setup.
Performance budget
Initial JS <= 10 KB
No WASM budget is declared, keeping the tool quick to open on mobile.
Best fit
Developer & DevOps · Developer
Category and role tags drive related tools, internal links, and quick fit checks.

How to use

  1. 1. Input

    Paste or drop your content into the tool panel.

  2. 2. Process

    Click the button. All processing is local in your browser.

  3. 3. Copy / Download

    Copy the result or download to disk in one click.

How HTTP Header Parser fits into your work

Use it in the small gaps between coding, reviewing, debugging, and shipping.

Developer jobs

  • Formatting, validating, shrinking, or inspecting code-adjacent text.
  • Preparing snippets for documentation, tickets, commits, or handoff.
  • Checking a small payload quickly without switching tools.

Developer checks

  • Run irreversible transforms like minify or obfuscate on a copy.
  • Keep secrets out of pasted snippets unless the tool explicitly stays local.
  • Use your normal tests or linter before shipping transformed code.

Good next steps

These links move the current task into a more complete workflow.

  1. 1 Unit Converter Convert between length, weight, temperature, area, volume, speed, time — instant, browser-only Open
  2. 2 Number Base Converter Number base converter — binary, octal, decimal, hex, and any base 2-36. Bitwise too. Open
  3. 3 HTTP Status Code Reference Every HTTP status code 1xx to 5xx with meaning, when-to-use and RFC, search by code or keyword, browser-only Open

Real-world use cases

  • Debug a failing API response in seconds

    An endpoint returns 401 and you do not know why. Paste the raw response from curl -i and read the table: was WWW-Authenticate sent, is the Content-Type actually application/json, did the server set a fresh cookie. Instead of squinting at a wrapped terminal dump you get one row per header with the value intact, so the missing or wrong header jumps out and you stop guessing.

  • Audit a site's security headers before launch

    Run curl -I against your staging URL and paste the headers. The security badges immediately show whether Strict-Transport-Security, Content-Security-Policy, X-Frame-Options and X-Content-Type-Options are present. A blank where a badge should be is your checklist of what to add before you ship, and you can copy the cleaned block into a ticket for the team.

  • Untangle a CORS preflight failure

    The browser console says a cross-origin request was blocked. Paste the OPTIONS response and look at the Access-Control-Allow-Origin, -Methods and -Headers rows side by side. Seeing the allowed origin and methods spelled out next to each other usually reveals the mismatch, a missing method or a wildcard that does not work with credentials, far faster than re-reading the spec.

  • Inspect every Set-Cookie a login flow returns

    A sign-in sets several cookies at once and you need to confirm the flags. Paste the response and each Set-Cookie lands on its own row with a duplicate badge, so you can check HttpOnly, Secure and SameSite on the session cookie without losing one in a merged line. The sensitive warning reminds you to redact the token before sharing.

Common pitfalls

  • Splitting a header on every colon instead of only the first. A Location URL like https://host:8443/x or a Date with times contains colons in the value, and splitting on all of them mangles the result. This tool splits once, on the first colon, and keeps the rest of the line as the value.

  • Merging duplicate Set-Cookie headers into one comma separated line. Cookies are the exception to header folding and must stay as separate lines, or flags like HttpOnly and SameSite get scrambled. Keep each occurrence on its own row.

  • Pasting headers that still contain a live Authorization token or session cookie into a shared link or a public ticket. Those values are credentials. Redact them first, and rely on the fact that this tool never puts the pasted block or sensitive headers into the URL.

Privacy

Every step of the parsing runs as plain JavaScript inside your browser tab. The header block you paste is never uploaded, logged or sent to any server, and there is no analytics on its contents. Only the sort order and the search keyword are written to the URL so a shared link reopens the same view. The pasted headers themselves, and any sensitive headers such as Authorization, Cookie or Set-Cookie inside them, are deliberately kept out of the URL so a share link can never leak a token. Even so, redact any real credential before you paste a block into a ticket or chat that other people can read.

FAQ

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Made by Toolora · 100% client-side · Updated 2026-05-29