Free SSL Checker: Test Your TLS Certificate Online
Checks the TLS certificate of a domain: issuer, remaining validity, TLS version, cipher suite and subject alternative names (SAN). Detects expired or soon-to-expire certificates and outdated protocols like TLS 1.0 or 1.1.
What does the SSL checker test?
The SSL checker fetches your domain's TLS certificate live and breaks it down into what actually matters: the issuing Certificate Authority and whether the full chain is served, the remaining validity with start and expiry dates, the negotiated TLS version (modern 1.2/1.3 versus the deprecated 1.0 and 1.1), the cipher suite and key strength, and every Subject Alternative Name (SAN) the certificate covers. At a glance you'll see whether example.com and www.example.com are both protected — or whether a subdomain slips through.
Why it matters
An expired certificate is the most avoidable outage on the web: browsers throw a full-page warning and visitors bounce before they ever see your site. Deprecated protocols are just as risky — TLS 1.0 and 1.1 have been considered insecure since 2021 and are rejected by modern browsers. A valid, up-to-date certificate is also a prerequisite for HTTPS, which Google treats as a ranking signal.
How to read the result
Green means a valid certificate, a complete chain, modern TLS and a strong cipher. Pay close attention to the remaining validity — under 30 days, plan the renewal (with Let's Encrypt this is automated via ACME). If TLS 1.0/1.1 shows up, disable it in your server or CDN configuration. A hostname missing from the SAN list will trigger a certificate warning for exactly that address. And if an unexpected CA appears, verify the certificate is really yours.
Frequently asked questions about SSL check
Is the SSL checker free?
Yes, completely free and no account needed — just enter a domain and check.
How often should I check my SSL certificate?
At least monthly, ideally with automated monitoring. Webscan Radar can monitor domains continuously and warn you before they expire.
What does “certificate expires in X days” mean?
The remaining validity. Under 30 days a renewal is due; once expired, browsers show a security warning.
Are TLS 1.0 and 1.1 still safe?
No. Both have been deprecated since 2021 and should be disabled in favour of TLS 1.2 and 1.3.
Need the full audit? The full Webscan Radar security check combines SSL check with all other areas plus GDPR audit, CMS detection, CVE matching and performance measurement in one report — also free.