See when any website's SSL certificate and domain registration expire. No signup needed.
Try it: watchmyssl.com, news.ycombinator.com, wikipedia.org
We connect to the site on port 443 the way a browser does and read the certificate it serves: who issued it, which names it covers, and when it expires. We also look up the domain's registration expiry date in the registry's whois record. A site can go down because either one lapses.
Every certificate has a fixed end date. Automatic renewal usually takes care of it, until it quietly doesn't: a DNS change breaks domain validation, a renewal hook stops reloading the web server, the card on a hosting account expires, or the certificate lives on a load balancer or CDN that nobody remembers. Often the first sign is a browser warning in front of your visitors.
The CA/Browser Forum voted to phase in shorter maximum lifetimes for public TLS certificates: 200 days from March 15, 2026, 100 days from March 15, 2027, and 47 days from March 15, 2029. More renewals means more chances for one of them to fail without anyone noticing.
Let's Encrypt stopped sending expiration reminder emails in June 2025. If those emails were your safety net, nothing warns you anymore when a renewal fails, unless you set up monitoring yourself.
Watch my SSL (dev) checks your certificates and domain registrations on a schedule and alerts you by email or Slack before they expire. It's free for your first domains.
Start monitoring for free