HTTP Security Header Checker
Audit pasted response headers locally for common browser security protections
About this tool
Audit pasted HTTP response headers for HSTS, CSP, clickjacking, MIME sniffing, referrer, permissions, and opener protections HTTP Security Header Checker runs in the browser on DevTools. There is no signup, and your input stays on this device unless the tool explicitly performs a live network lookup.
What this tool does not do
- HTTP Security Header Checker is a free in-browser utility, not a hosted API. It does not keep server-side history and is not a substitute for production verification in your own stack.
How do I use this tool?
How do I use HTTP Security Header Checker?
Open HTTP Security Header Checker, enter or paste your input, and copy the result. The page works without an account.
Related guides
Security Headers Checker — Grade and Fix HTTP Response Headers
Fetch live headers, get an A–F grade, and read MDN-linked fixes for HSTS, CSP, clickjacking, and more. Fix the failing headers in deployment order.
Content-Security-Policy: Build It Right, Then Audit It
A practical guide to authoring a strong Content-Security-Policy and auditing one you already ship. How default-src, unsafe-inline, wildcards and frame-ancestors affect your real XSS protection.
HTTP Security Headers Explained: HSTS, CSP, and the Rest
A practical guide to response security headers. What HSTS, Content-Security-Policy, X-Frame-Options, X-Content-Type-Options, Referrer-Policy and Permissions-Policy actually do, and the weak values to avoid.
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