SSL Checker: make sure your certificate does not quietly expire
There is one small nightmare many site owners experience: wake up in the morning, open your own site, and get greeted by a red "connection not secure" page. The cause is almost always the same, an SSL certificate that expired without anyone noticing. This tool exists so you never reach that point.
Enter a domain, and in an instant you will see who issued the certificate, when it starts, when it ends, how many days remain, and which domains it protects. Everything is read straight from the live TLS connection to the server, so what you see is the real state, not a guess.
Why certificates matter beyond the green padlock
HTTPS is not just decoration. Without valid encryption, data passing between your visitor and server can be snooped. Modern browsers are increasingly strict too; a site without healthy HTTPS gets ranked lower and flagged as suspicious. For an online store, even one hour of a dead certificate can mean abandoned transactions and trust that is hard to rebuild.
The most common problems
- Incomplete chain. The server forgets to send the intermediate certificate. Desktop browsers may forgive it, but mobile apps and APIs fail right away. Always install the full chain.
- Name mismatch. A certificate for domain.com but accessed via www.domain.com without coverage. Make sure all variants are in the SAN list.
- Nearly expired. If only a dozen days remain, renew immediately. Do not cut it close.
Make auto-renew a habit
If you use Lets Encrypt, certificates only last 90 days, so automatic renewal is mandatory. For annual paid certificates, set a reminder well ahead. Check periodically with this tool, especially near critical dates, so there are no unpleasant surprises in the morning.