Free SSL Certificate Checker — Expiry & Coverage
Before you trust a site — or when you manage one — the SSL Checker pulls live certificate data from Certificate Transparency logs: who issued it, when it expires, and every domain name it covers. Great for verifying Let's Encrypt renewals and spotting missing SAN entries.
🔒 100% Private — runs in your browser, nothing is uploadedHow to Use This SSL Certificate Checker (Step-by-Step)
- Enter a domain — example.com — no https needed.
- Click Check SSL — Public Certificate Transparency logs are queried.
- Review expiry and coverage — Days remaining, issuer and every SAN name appear.
Certificate Transparency Explained — Under the Hood
Since 2013 every CA must publish issued certificates to public append-only logs. crt.sh indexes those logs, so you can audit any domain's cert history without contacting the site — which is also why attackers use CT logs for subdomain enumeration.
Frequently Asked Questions
Where does the data come from?
crt.sh (Certificate Transparency logs) — the same public ledger browsers use.
Does it check the live handshake?
No — it reads issued certificates. For protocol grading use an SSL Labs scan.
Why do I see multiple certificates?
Domains often have several valid certs (www vs apex, renewals); the newest is highlighted.