SSL Certificate Checker

Check SSL certificate validity, expiry and issuer

Free

Works great with these tools

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Frequently asked questions

Common questions people ask before using this tool.

What does an SSL certificate checker validate?

It inspects the TLS certificate served by a hostname: issuer, validity dates, chain of trust, and SANs (Subject Alternative Names). Use it to catch expired certificates, hostname mismatches, or incomplete certificate chains that trigger browser security warnings.

Does HTTPS / SSL affect SEO?

Yes. Google has used HTTPS as a lightweight ranking signal since 2014. Beyond SEO, HTTPS protects users from data interception, is required for modern browser features (Service Workers, HTTP/2), and builds trust with visitors who see the lock icon.

Why does my site show "Not Secure" even with SSL installed?

Common causes include mixed content (HTTP assets loaded on HTTPS pages), an expired or self-signed certificate, the SSL certificate not covering your exact domain (www vs non-www), or an incomplete certificate chain. This tool helps identify which issue applies.

How often should I check my SSL certificate?

Check at least 30 days before your certificate expires to allow time to renew. If you use automated renewal (Let's Encrypt with Certbot or a similar tool), monitor renewal logs weekly. An unexpected certificate change can indicate a misconfiguration or security issue.

What is the difference between DV, OV, and EV SSL certificates?

DV (Domain Validated) certificates verify you control the domain — issued in minutes and free with Let's Encrypt. OV (Organization Validated) also verifies your business identity — takes days. EV (Extended Validation) provides the highest identity assurance — typically used by banks and large enterprises. All three provide the same level of encryption.

What is a certificate chain and why does it matter?

Your SSL certificate is signed by an intermediate CA, which is signed by a root CA that browsers trust. The "chain" links your cert to the trusted root. If the intermediate is missing from your server's configuration, some browsers show a "certificate not trusted" error even though your cert is valid.

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