SSL Certificate Checker

Is the padlock in the browser really fine?

An SSL certificate is what lets your site run over HTTPS and show the padlock next to the address. If it expires or is set up wrong, visitors get a big red warning saying the connection is not secure, and most of them leave on the spot. Jood's SSL certificate checker connects to your site the way a browser does and tells you whether the certificate is trusted, when it expires and which domains it covers.

How to use it

1. Type the domain in the "Domain Name" box, such as example.com, or paste a full address.
2. Click "Start Now".
3. The verdict appears at the top: "Trusted and valid certificate" in green, or "Untrusted certificate" in red with the reason.

What the tool checks

• Trust: was the certificate issued by a known authority that browsers trust, with a complete chain leading to it?
• The name: is the domain you typed listed in the certificate? A certificate for *.example.com works for shop.example.com, but only covers example.com itself if that name is listed too.
• The dates: is the certificate valid right now, when does it expire, and how many days are left?

The tool also shows the "Issuer", such as Let's Encrypt, and the "Covered domains", meaning every name the certificate protects. The check runs on port 443, the standard HTTPS port.

The usual reasons for a failure

• Expired certificate: automatic renewal stopped, or was never set up.
• Self-signed certificate: the server made it for itself, so no browser trusts it. Fine for testing only.
• Name mismatch: for example, a certificate for example.com alone while visitors open www.example.com.
• Incomplete chain: the server does not send the intermediate certificate. Chrome sometimes opens the site anyway, but other apps and some phones refuse it.

Habits that prevent nasty surprises

• Test the domain with and without www, and make sure both names are in the list of covered domains.
• Free Let's Encrypt certificates are usually renewed automatically about a month before they expire. If yours shows fewer days left than that, check that automatic renewal is working.
• Run the check again after every site move, hosting change or change to your Cloudflare settings.

If the site does not open at all, use Is the Website Down Right Now?, and to see security headers such as HSTS, the HTTP headers checker.