What an SSL certificate does
An SSL/TLS certificate proves a website is who it claims to be and encrypts the connection between your browser and the server. It's what turns http into the padlocked https. Without a valid certificate, browsers warn visitors away.
What to check
- That the certificate is valid and not expired.
- That it covers the exact name you use, including www if needed.
- That it uses a modern TLS version (1.2 or 1.3).
Want to dig deeper into a site? Check its HTTP headers or run a WHOIS lookup.
Frequently asked questions
What does this SSL checker do?
It connects to a domain over HTTPS and reads its certificate, then shows who issued it, when it expires, which names it covers, and the TLS version in use.
Why does my certificate expiry matter?
When a certificate expires, visitors see a security warning and may not be able to reach your site. Most certificates auto-renew, but it's worth checking if you manage your own.
What is TLS?
TLS is the encryption behind HTTPS. Modern sites should use TLS 1.2 or 1.3. Older versions are considered insecure.