Security
SSL Certificate Checker
Inspect a site's SSL/TLS certificate — issuer, expiry date, and trust chain — via a real TLS handshake.
About this tool
Comprehensive documentation & audit utility guideAn SSL/TLS certificate is what lets a browser verify it's really talking to the domain it thinks it is, and encrypts the connection along the way. This tool opens a real TLS handshake to the target and inspects the certificate the server actually presents — the same certificate every visitor's browser sees.
How it works
1
Enter a URL
Any public https:// site.
2
We open a TLS handshake
A real connection to port 443, just like a browser makes.
3
Review the certificate
Issuer, validity window, trust chain, and every domain it covers.
What it checks
Certificate issuer and subject
Valid-from / valid-to dates and days remaining
Whether the chain is trusted by default root CAs
Negotiated TLS protocol version
All Subject Alternative Names (SANs) covered