SSL Certificate Checker
Check SSL/TLS certificate expiry, issuer, and domain coverage for any website.
About SSL Certificates
SSL/TLS certificates are digital documents that cryptographically bind a domain name to an organization and a public key. Browsers use them to establish encrypted HTTPS connections and verify that you are actually communicating with the intended server (not an impersonator).
An expired certificate causes immediate browser warnings that block most users. Certificate monitoring should be part of every organization's production operations practice.
What This Checker Reports
- Expiry date — days remaining before the certificate expires
- Issuer — the Certificate Authority (CA) that issued the certificate
- SANs — all domain names the certificate covers
- Certificate chain — the full trust chain from leaf to root CA
- Domain coverage — whether the cert covers the hostname you entered
Frequently Asked Questions
How far in advance should I renew an SSL certificate?
Renew at least 30 days before expiry. Let's Encrypt renews 30 days before expiry by default. Many organizations renew 60–90 days early for safety.
What is a wildcard certificate?
A wildcard certificate (e.g. *.example.com) covers all immediate subdomains.
It does NOT cover nested subdomains (e.g. sub.api.example.com).
What is a certificate chain?
A chain of trust where each certificate is signed by the next: your server cert → intermediate CA → root CA trusted by browsers. An incomplete chain causes "untrusted certificate" warnings.
What is the difference between DV, OV, and EV certificates?
DV (Domain Validation) only verifies domain ownership — fast, cheap, used by Let's Encrypt. OV (Organization Validation) also verifies the organization's legal identity. EV (Extended Validation) requires strict identity vetting — used by banks and high-trust sites.