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HSTS · Preload · Security Headers

HSTS Preload Checker

Check if your domain is in the Chrome HSTS preload list, ensuring browsers always use HTTPS — even on the very first visit.

HSTS Preloading goes further than a normal HSTS header — your domain is hardcoded into browsers (Chrome, Firefox, Safari, Edge) so HTTPS is enforced before any HTTP connection is attempted.

To qualify, your domain must serve a valid HSTS header with max-age≥31536000; includeSubDomains; preload and be submitted at hstspreload.org.

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