SSL Certificate Checker
Check any domain’s SSL/TLS certificate — issuer, expiry date and covered domains — instantly in your browser via Certificate Transparency.
What this tool shows
Enter a domain and this checker finds its current publicly-trusted certificate from Certificate Transparency logs and shows:
- Validity — whether the certificate is valid, expiring soon, or expired, with days remaining.
- Issuer — the Certificate Authority that signed it.
- Dates — when it was issued and when it expires.
- Covered domains (SANs) — every host name the certificate is valid for.
- A short history of recent certificates seen in CT logs.
Common uses
- Get ahead of expiry so your site never serves an expired certificate.
- Confirm a renewal was issued and picked up the right domains.
- Check which CA issued a certificate (and spot unexpected issuers).
- Verify a wildcard or multi-domain certificate covers every host you expect.
- Pair it with a DNS lookup and the domain’s WHOIS record for a full picture.
Frequently asked questions
How does this SSL checker work without connecting to my server?
It reads public Certificate Transparency (CT) logs. Every publicly-trusted certificate must be logged to CT, so the current certificate for a domain — its issuer, validity dates and covered names — appears there. This is a CT-based check rather than a live TLS handshake.
How do I check when an SSL certificate expires?
Enter the domain and read the Expires row. The tool highlights certificates expiring within 30 days and flags expired ones, and shows exactly how many days remain.
What are SANs (covered domains)?
Subject Alternative Names are all the host names a single certificate is valid for — for example example.com, www.example.com and *.example.com. The tool lists every covered name.
Who issued the certificate?
The Issuer row shows the Certificate Authority — for example Let's Encrypt, Google Trust Services, Sectigo or DigiCert.
Is my check private?
The tool has no backend and stores nothing. The domain you check is sent to the public Certificate Transparency API. Nothing else leaves your device.