Pro move: type dmarc:yourdomain.com or blacklist:1.2.3.4 straight into the box — it switches tools for you.
About this tool. Confirms your site answers over HTTPS with a certificate our edge trusts, times the response, and reports the security headers that matter (HSTS and friends).
How to read your https & ssl checker results
We connect over HTTPS and report TLS reachability, redirects, and key security headers like HSTS.
A successful HTTPS response means the certificate is valid and trusted by our edge. Missing security headers are worth adding.
Common problems and how to fix them
HTTPS works but security headers are missing
Add HSTS, and consider a content security policy and other standard headers, to harden the site.
Certificate errors
Renew or reissue the certificate, and make sure the full chain is served, not just the leaf certificate.
Common questions.What does an HTTPS check verify?
That the site answers over TLS with a valid certificate, how it redirects, and which security headers it sends.
What is HSTS?
HTTP Strict Transport Security. A header that forces browsers to use HTTPS for your site, preventing downgrade attacks.