Security
HTTP security header test
Score HTTP security headers (HSTS, CSP, XFO…).
HSTS, CSP, X-Frame-Options, nosniff, Referrer-Policy and Permissions-Policy harden the browser. Gaps affect the letter grade.
If HEAD is unsupported, GET is tried. Redirects never follow into private networks (SSRF protection). The grade is guidance, not a pentest.
HSTS max-age and includeSubDomains matter for HSTS preload. CSP unsafe-inline widens XSS. Cross-Origin-Opener-Policy improves isolation.
Frequently asked questions
Why is the grade low without CSP?
CSP is the strongest XSS-related header. Its absence drops the score a lot.
Why is the grade low without HTTPS?
Most of these headers only make sense on HTTPS. Certificate first, then headers.
Is X-Powered-By bad?
It leaks the stack. Removing it reduces disclosure; it affects the grade a little.
Are redirects followed?
Only same-host public URLs. Private-network IPs are not followed.
How do I get an A+?
HSTS, a tight CSP, nosniff, Referrer-Policy and frame controls together. Not every site needs A+.