SSL Certificate Checker
Certificates issued for a domain, pulled from public Certificate Transparency logs (crt.sh) — issuer, validity dates and expiry status.
Check the SSL certificate of any website — validity dates, covered domains and revoked or expired certificates — using public Certificate Transparency logs. No account needed, results in seconds.
Data: public Certificate Transparency logs (certspotter API).
How to use the SSL Certificate Checker
- Enter a domain name.
- Certificates are pulled from CT logs and listed newest first.
- Green = valid, red = expired or revoked — check the date range shown.
Frequently asked questions
How do I check if a site's SSL certificate is valid?
Enter the domain above — the checker lists its certificates from public CT logs with validity dates and status.
Where does the certificate data come from?
Public Certificate Transparency logs, which record every publicly issued certificate.
What does 'revoked' mean?
The certificate was cancelled before its expiry date, usually after a key compromise or mis-issuance.
Why do I see multiple certificates?
Sites renew certificates regularly, often every 90 days. Older, non-expired ones still appear in logs.
Fun facts about SSL Certificate Checker
- SSL/TLS certificates use public-key cryptography — the certificate contains a public key that browsers use to establish an encrypted connection.
- Let's Encrypt, launched in 2015, provides free SSL certificates and now secures over 300 million websites — making HTTPS the default rather than the exception.
- Certificate Transparency (CT) logs are public, append-only records of all issued SSL certificates — they were created to detect mis-issued or fraudulent certificates.
- The padlock icon in your browser's address bar indicates a valid SSL certificate — but it doesn't guarantee the website is trustworthy, only that the connection is encrypted.
- Certificate lifetimes are shrinking: the maximum for publicly trusted certificates fell from 398 to 200 days in March 2026 and is scheduled to reach 47 days in 2029; Let's Encrypt issues 90-day certificates.