Free SSL Certificate Checker: Validity, Expiry, Chain, and TLS Version

What an SSL certificate checker looks at, and why it matters

An SSL certificate checker confirms that the small file your server uses to open an encrypted (HTTPS) connection is healthy. Your SSL/TLS certificate lets a browser confirm the site is really yours and encrypt the traffic between you. When it is healthy, visitors see a padlock and nothing else. When it is wrong, browsers throw a full-page warning that most people will not click past, and your traffic, sales, and trust drop on the spot.

A good SSL certificate checker looks at four practical things. First, validity: is the certificate actually issued for this domain name and signed by a trusted authority. Second, expiry: certificates are time-limited, and an expired one breaks the padlock instantly. Third, the trust chain: browsers need the full path from your certificate up to a root they recognise, and a missing intermediate is a common cause of "works in my browser but not on someone else's phone." Fourth, the protocol version: retired TLS versions (TLS 1.0 and 1.1) and weak settings leave the connection less secure than the padlock suggests.

A certificate problem is rarely just cosmetic. A misconfigured or expired certificate can quietly block legitimate customers, fail payment integrations, and signal to attackers that a site is unmaintained. It is one of the most visible parts of your public security posture, which is exactly why it is worth checking on a schedule rather than waiting for the outage.

How BadgerScan checks it

BadgerScan is not a separate single-purpose tool. The SSL/TLS check is one part of one free, passive external scan. When you run a scan from the BadgerScan home page, we connect to your site the same way a browser would, read the certificate your server presents, and report on its validity, expiry date, chain, and the TLS protocol on offer, alongside your DNS, email security, HTTP security headers, exposed files, and any known CVEs for publicly-detectable software versions.

The scan is read-only and passive. We look at what your server already shows the public internet. BadgerScan never performs penetration testing, never tries to exploit anything, and never touches the inside of your site during the free scan. You get one plain-English grade and one combined fix-list covering everything we saw from the outside, not six disconnected tool reports to stitch together yourself.

How to read your result

A passing certificate result means the certificate matches your domain, is signed by a trusted authority, presents a complete chain, has comfortable time left before expiry, and negotiates a modern TLS version. That is the green-padlock state you want, and there is nothing to do.

A warning usually points to one specific cause. "Expiring soon" means renew before the date shown so the padlock never breaks. "Name mismatch" means the certificate was issued for a different host (often www versus the bare domain, or an old domain you have moved off). "Incomplete chain" means the certificate itself is fine but your server is not sending the intermediate certificate, so some devices reject it even though yours accepts it. "Outdated protocol" means your server still allows a retired TLS version and should be tightened.

Because the certificate result sits inside the combined grade, you can see how it stacks up against the rest of your external posture. A perfect certificate does not rescue a site that is leaking config files, and the single grade is designed to stop one green checkmark from hiding a real problem elsewhere.

Common fixes

Most certificate issues are quick to resolve once you know which one you have:

• Expired or expiring: renew the certificate now. If you use Let's Encrypt or a host-managed certificate, enable or repair auto-renewal so this never recurs.
• Name mismatch: reissue the certificate to cover the exact hostname visitors use, and make sure both the bare domain and the www version are served correctly (a SAN or wildcard certificate, plus a redirect to your canonical host).
• Incomplete chain: install the intermediate certificate your authority provides (the "full chain" or "bundle" file) so every device can build the path to a trusted root.
• Outdated TLS: disable TLS 1.0 and 1.1 on your server or CDN and serve TLS 1.2 and 1.3 only. Most managed hosts and Cloudflare-style proxies let you set the minimum version in one setting.
• Mixed content after fixing the certificate: update any hard-coded http:// links and assets to https:// so the padlock is not downgraded by insecure resources on the page.
• Not sure who manages it: if your certificate is handled by your host, CDN, or a developer, send them the specific warning from your scan so the right person fixes the right setting.