HTTP Header Parser
Paste raw HTTP headers and get each one parsed, validated and explained in plain English.
This tool runs 100% in your browser. Your data is never uploaded, stored, or logged.
Parsed headers
Paste request or response headers — each one is parsed and explained.
About this tool
Response headers decide caching, security, CORS and content handling — but raw header blocks are dense reading. This parser splits a pasted request or response into a clean table and explains what ~40 common headers actually do, from Cache-Control to Strict-Transport-Security.
Status lines are decoded too, with the status code classified at a glance.
How to use it
- Copy headers from DevTools (Network tab → Raw), curl -i output, or logs.
- Paste them into the input.
- Read the parsed table — name, value, and meaning for each header.
- Malformed lines are flagged separately so you can spot typos.
Useful ways to apply it
- Debugging caching behavior via Cache-Control, ETag and Vary.
- Auditing security headers before a deployment.
- Understanding CORS responses during cross-origin debugging.
- Teaching juniors what each header in a response does.
Frequently asked questions
Does it accept request and response headers?
Both. A leading status line (HTTP/1.1 200 OK) or request line (GET /path HTTP/1.1) is detected and decoded; plain header lists work too.
What counts as malformed?
Any non-empty line without a colon-separated name. These are listed under the table so you can fix them.
Are custom headers supported?
Yes — unknown and X- headers are parsed normally and labeled as custom.
Privacy
This tool runs 100% in your browser. Your data is never uploaded, stored, or logged.