HTTP Headers Checker
Inspect HTTP/HTTPS response headers, status codes, redirects, and missing security headers for any URL.
Security headers explained
Strict-Transport-SecurityForces HTTPS — prevents protocol downgrade attacks (HSTS)
Content-Security-PolicyRestricts which resources the browser can load — mitigates XSS
X-Content-Type-Optionsnosniff — prevents MIME-type sniffing attacks
X-Frame-OptionsDENY or SAMEORIGIN — prevents clickjacking via iframes
Referrer-PolicyControls how much referrer info is sent with requests
Permissions-PolicyRestricts browser features (camera, geolocation, etc.)