Parse and view HTTP headers online

How it works

1. 1

   Copy the raw headers from your terminal or developer tools.

2. 2

   Paste them into the box.

3. 3

   Read the parsed list and explanations.

About the HTTP Header Viewer

Raw HTTP headers copied from curl -I, browser developer tools or a proxy log are a wall of Name: value lines. This viewer splits them into a tidy list, pulls out the status or request line, and adds a short explanation next to well-known headers such as Cache-Control, Content-Security-Policy and Strict-Transport-Security, so you can see what a response is telling the browser.

What you can do

• Paste request or response headers and see each one as a name and value pair.
• Show the first line without a colon, such as HTTP/1.1 200 OK or GET / HTTP/1.1, separately.
• Read one-line explanations for common headers covering caching, cookies, CORS, redirects and security.
• Keep repeated headers such as several Set-Cookie lines as separate entries.

When it works best

• Checking why a page is being cached, or not cached, from its Cache-Control, ETag and Vary headers.
• Reviewing whether a site sends security headers like X-Frame-Options and HSTS.
• Reading the headers in a bug report when a CORS or redirect problem only happens in one environment.

Things to know

• Headers are parsed in your browser. Remove Authorization and Cookie values before pasting into any tool or ticket.
• The tool reads text you paste; it does not fetch a URL to collect headers itself.
• Explanations cover about twenty common headers, and values are not checked for mistakes.
• To build a request with custom headers, use the cURL Builder. To decode a browser string, use the User-Agent Parser.

Frequently asked questions