What this checker shows
Enter a domain and SYNAPSE opens a live TLS connection to read the exact certificate the server presents: the issuing authority, the subject and Subject Alternative Names (every hostname the cert covers), the issue and expiry dates, and the days remaining before it lapses. It also shows the key type and strength, the full certificate chain (leaf → intermediate → root), and whether the certificate is trusted, all quick signals of a healthy, modern HTTPS setup.
Frequently asked questions
What does an SSL checker do?
It performs a live TLS handshake with the site and reads the certificate the server actually presents: who issued it, which hostnames it covers, when it was issued, and when it expires. That lets you confirm the certificate is valid, trusted, and won't lapse unexpectedly.
How do I know when my SSL certificate expires?
Enter your domain above and the checker shows the exact expiry date and the number of days remaining. An expired certificate makes browsers show a security warning, so most teams renew well before the deadline.
What does "Trusted" mean?
Trusted means the certificate chains up to a certificate authority your system already trusts and isn't expired or misconfigured. Untrusted flags a problem (a self-signed cert, a broken chain, an expired cert, or a hostname mismatch) that browsers will warn about.
What are SANs?
Subject Alternative Names are the hostnames a single certificate is valid for, e.g. example.com and www.example.com. The checker lists them so you can confirm every hostname you serve is covered.