Free SSL Certificate Checker

What this tool checks

We open a TLS connection to the host you provide and read the certificate the server presents — the same handshake your browser performs. From the certificate we extract:

• Issuer (Certificate Authority) — who signed it (Let's Encrypt, DigiCert, Cloudflare, etc.)
• Valid from — when the certificate became active
• Valid to — when the certificate expires
• Days remaining — color-coded: green if >30 days, yellow if 7–30, red if <7 or expired

We do not store the result, log your IP for marketing, or track you across the rest of the site.

Why SSL expiry matters

Expired certificates cause browsers to block your site with a full-page security warning. Visitors who see that warning rarely proceed — they leave. Worse, expired certificates also break server-to-server connections (APIs, webhooks, payment integrations) that fail silently for hours before anyone notices.

Most expired-cert outages are preventable. They happen because the certificate was managed by an ex-employee, a renewal cron failed quietly, or a domain ownership change broke ACME validation. Catching the trend a week before expiry gives you time to fix the renewal pipeline, not scramble during an outage.

Frequently asked

Does this work on non-standard ports? Yes — append `:port` to the domain (e.g. `mail.example.com:465`).

Will it work on internal/private hosts? No. We block private and loopback addresses to prevent server-side request forgery.

What if the certificate is self-signed? We'll still return the issuer and validity, with a note that it's self-signed.