SSL Certificate Checker
Inspect any domain's SSL/TLS certificate — issuer, validity dates and expiry status.
About this tool
This tool connects directly to the domain on port 443 and reads its live SSL/TLS certificate — the same certificate a visitor's browser would see. Use it to confirm a certificate is valid, correctly issued, covers the right hostnames, and isn't close to expiry.
What the results mean
- Common Name / Alternative Names — the hostname(s) the certificate is actually issued for. If your domain isn't listed, browsers will show a security warning.
- Issuer — the certificate authority (CA) that issued it, e.g. Let's Encrypt, DigiCert, or Sectigo.
- Valid From / Valid To — the certificate's active date range. Most free certificates (like Let's Encrypt) are valid for 90 days and renew automatically; commercial certificates are often valid for a year.
- Status — flags certificates that are expired or expiring within 14 days, since an expired certificate breaks HTTPS entirely for visitors.
Why SSL certificates matter
An SSL/TLS certificate encrypts traffic between a visitor's browser and your server, and proves the site is genuinely who it claims to be. An expired or misconfigured certificate causes browsers to show a full-page security warning, which can devastate trust and traffic overnight — this tool is designed to help you catch that before visitors do.
My domain has SSL but this tool says it can't connect
Double-check the domain actually serves HTTPS on port 443 (not just a redirect page), and that no firewall is blocking external connections to that port.
How often should I check my SSL certificate?
If you use free auto-renewing certificates (e.g. Let's Encrypt via your host), renewal usually happens automatically — but it's still worth checking after any hosting or DNS change, since a broken renewal process often goes unnoticed until the certificate actually expires.
Related tools: