SSL certificate checker
Enter a domain to see who issued its certificate, when it expires, which names it covers, the full chain and the TLS version your server negotiates.
What this checker looks at
We open a TLS connection with SNI to the host (port 443 by default; 465, 636, 853, 993, 995 and 8443 are also allowed) and read the certificate the server presents.
“Trusted” means the chain validates against the standard Node.js / Mozilla root store for that hostname. A certificate can be valid in time but still untrusted — for example if an intermediate is missing or the name does not match.
Expiring certificates are one of the most common avoidable outages. A one-off check tells you today’s state; a TLS monitor reminds you before it is too late.
+Is the SSL checker free?
Yes. No account is needed. To prevent abuse there is a per-IP rate limit of a few checks per minute.
+Why is my certificate shown as “not trusted”?
Usual causes are a missing intermediate certificate on the server, a self-signed or private-CA certificate, an expired certificate, or a hostname that is not covered by the certificate’s SANs.
+Which TLS versions are good?
TLS 1.3 and TLS 1.2 are current. TLS 1.0 and 1.1 are deprecated and rejected by modern browsers.
+Can I check internal hosts?
No. For security reasons the tool refuses private, loopback, link-local and other reserved addresses.
+How do I get notified before expiry?
Create a free uptime.bet account and add a TLS monitor for the host. You will get an email or webhook alert before the certificate runs out.
Get warned before this certificate expires
A one-off check is a snapshot. Add a TLS monitor and uptime.bet alerts you by email or webhook days before expiry — free plan, no credit card.
uptime.bet is in a public test phase: free to use, no warranty, billing not enabled yet.