Security Headers Checker
Inspect common browser security headers including HSTS, CSP, X-Frame-Options and Referrer-Policy.
How to interpret the result
Treat each lookup as a point-in-time observation. DNS can change, registration data can be redacted, CDNs can obscure origin infrastructure, and third-party intelligence providers can have coverage limits.
About Security Headers Checker
Inspect common browser security headers including HSTS, CSP, X-Frame-Options and Referrer-Policy. WHOISDR presents the returned data with context so you can decide which related lookup to run next. Results should be verified against the authoritative provider when you are making operational, legal or security-sensitive decisions.
Current-state checks
Free tools focus on live public data and diagnostic signals available at the time of the request.
Actionable follow-ups
Use related DNS, registration, network and web tools to verify a finding rather than relying on one signal in isolation.
Pro investigation workflow
Save evidence snapshots, export CSV, run bulk lookups and combine current data with historical intelligence.