// free tool

SSL certificate checker

See when a site's certificate expires, who issued it, which domains it covers, and whether browsers trust it. One lookup, nothing stored.

What this checks

  • Expiry: the exact date and days remaining on the certificate the server presents.
  • Trust: whether the chain verifies against standard browser roots and matches the hostname. A self-signed, expired or mismatched certificate fails here.
  • Coverage: every hostname listed on the certificate, so you can see whether www and the bare domain are both covered.
  • Issuer and TLS version: who issued it and which protocol version the server negotiated.

Why certificates still expire with auto-renewal on

Auto-renewal fails quietly more often than people expect: a DNS change breaks the validation challenge, a CDN or load balancer keeps serving an old certificate, a renewal hook never reloads the web server, or the site moved hosts and the old renewal job kept running somewhere else. A one-off check tells you today's state. Monitoring tells you before the date arrives.

Limits

Port 443 only, public domains only, and a few lookups per minute per visitor. We do not store the domains you check.