SSL certificate checker
Check the expiry date, issuer and validity of any website’s HTTPS certificate.
Why monitor your certificate?
An expired certificate makes a website unreachable: browsers show a security warning and most visitors leave. It is one of the most common outages, and the easiest to avoid.
- Let’s Encrypt certificates last 90 days and automatic renewal can fail silently.
- A certificate can be valid but issued for another name (misconfiguration after a migration).
- An incomplete chain works in some browsers but not in others.
What the tool checks
The tool connects to port 443, fetches the presented certificate and checks the trust chain and the name. It shows the validity dates, the issuer and the covered names (SAN).
Alerts before expiry
MoniProbe checks your certificates every day and warns you 14, 7, 3 and 1 day before they expire, for free.
Other free tools
Is it down?
Check whether a website responds, from our servers, with every step detailed.
Domain expiry
Expiry date and registrar of a domain name (RDAP).
Security headers
HSTS, CSP, X-Frame-Options… A grade and advice for each header.
DNS lookup
A, AAAA, CNAME, MX, TXT, NS and CAA records of a domain.
Blacklist check
Check an IP or a domain (and its mail servers) on Spamhaus, Barracuda, SpamCop and other lists.