SSL checker
Enter a domain and see its certificate: who issued it, how long it is valid, which host names it covers and whether browsers trust it.
Frequently asked questions
What does the SSL checker show?
Issuer, subject, validity period and remaining days of the certificate, the host names it covers (SAN), whether the chain is trusted and matches the domain, and the negotiated TLS version.
Why is my certificate shown as not trusted?
Usually an intermediate certificate is missing on the server, the certificate is self-signed or expired, or it does not cover the domain you entered. Browsers then show a warning.
Which port is checked?
Port 443 (HTTPS) of the domain you enter. Only public addresses can be checked.
How does Kaspar warn me before a certificate expires?
For HTTPS uptime monitors, Kaspar checks the certificate and warns you 30, 14, 7 and 1 day before it expires.
Are the results stored?
No. The results are only shown to you in this response and are not saved.