HTTP Header Checker
Inspect response headers and audit security headers.Web & SEO ToolsHTTP Header Checker
Inspect a URL's response headers and audit the important security headers. Requests go through a rate-limited proxy that blocks private addresses.
About this tool
See every response header of the final hop, plus a focused audit of the important security headers with plain-language explanations for anything missing.
How to use the HTTP Header Checker tool
- Enter the URL. Absolute, with protocol.
- Check. The final response headers are listed and audited.
- Fix the gaps. Missing security headers are flagged with what they do.
Supported formats
Input
- Plain text or file input
Output
- Converted or analysed output
Inputs are validated before anything is processed. Invalid values and unsupported files are rejected with a clear error instead of failing silently.
Frequently asked questions
Which security headers are audited?
HSTS, Content-Security-Policy, X-Content-Type-Options, X-Frame-Options and Referrer-Policy.
Is the request cached?
No; every check is a fresh request through the proxy.
Are cookies shown?
Set-Cookie headers are hidden by the fetch layer for safety.
Privacy
Everything you enter stays in this browser tab. There is no upload endpoint for tool inputs, no account, and no server-side copy of your text or files. Results are produced locally and disappear when you close the page.
No account is required and no file is ever uploaded. See the privacy policy for details about analytics and the limited data this site stores.
Known limitations
- Header values beyond the 1 MB response cap are truncated.
Related tools
Other free tools from the same collection.