SSL Certificate Checker

Check SSL/TLS certificate details for any domain. See expiry dates, issuer, SANs, and connection security.

How It Works

Enter a domain

Type a domain name like example.com. No protocol or path needed — the tool connects directly to port 443.

See certificate details

View the subject, issuer, validity dates, days remaining, serial number, SHA-256 fingerprint, and Subject Alternative Names.

Check status

A color-coded badge shows whether the certificate is valid, expiring soon (under 30 days), or expired.

FAQ

The certificate is valid but expires within 30 days. Most certificate authorities recommend renewing at least 30 days before expiry to avoid downtime.

Subject Alternative Names — additional domain names covered by the certificate. For example, a cert for example.com might also cover www.example.com and api.example.com.

Any publicly accessible domain with HTTPS on port 443. Internal or non-standard port certificates can't be checked.

The TLS protocol version (e.g. TLSv1.3) and cipher suite (e.g. TLS_AES_256_GCM_SHA384) negotiated during the connection. These indicate the encryption strength. For checking CORS and other headers, try the CORS tester.

Built & Maintained by Varstatt

Varstatt is a one-person product studio run by Jurij Tokarski, product engineer since 2011. These tools are free and open — no signup, no catch.