SSL Certificate Checker
Verify the SSL/TLS certificate for any domain.
What is an SSL Certificate?
An SSL (Secure Sockets Layer) certificate encrypts data transmitted between a web server and a browser. When a site has SSL, you'll see a padlock icon and "https://" in the address bar.
SSL certificates are essential for security, user trust, and SEO. Google uses HTTPS as a ranking signal, and browsers now warn users about non-secure sites.
Certificates come in three validation levels: Domain Validated (DV), Organization Validated (OV), and Extended Validation (EV). Free certificates from Let's Encrypt provide DV-level security suitable for most websites.
This tool fetches the TLS certificate that a host presents and reports the fields that matter when you are checking what a site is actually serving.
What the report actually contains
The output is a structured view of the certificate as presented on the wire. You get the issuer, the commonName, and the subject alternative names (SANs), which tell you which hostnames the certificate covers. The validity window is given as validFrom and validTo dates, so you can see at a glance whether the certificate is currently within its period. The tool also reports the TLS version and cipher suite negotiated during the fetch, plus the HTTP status and any redirect the server returned. Finally, a single valid flag summarizes whether the certificate is currently valid based on the dates and hostname match.
What it does not claim to check
This is a point-in-time snapshot of the presented certificate, not a full chain-of-trust audit. It does not build a trust path to a root CA, check for revocation, or scan for vulnerabilities in the TLS configuration. It also does not issue a letter grade — the report is a set of facts, not a score. The tool reads the current record only; it does not show a history of past certificates or changes. If you need a deeper audit, you would look elsewhere. For a quick check of what a server is currently sending, this tool gives you the raw fields without interpretation.
How to read the valid flag
The valid flag is a Boolean that the tool computes from the data it gathered. It tells you whether the certificate is currently valid in the narrow sense: the current time falls between validFrom and validTo, and the hostname you queried matches one of the commonName or SAN entries. It does not account for trust anchors, intermediate certificates, or revocation status. If the flag is true, the certificate is at least syntactically and temporally valid for that host. If it is false, the report shows which field is out of line — check the dates and the SAN list to see why. The tool does not tell you why it is invalid; it gives you the data to reason about it.
When to use this tool alongside others
This checker is useful as a first step when you suspect a certificate problem, such as a mismatch or an expiry. But because it only reads the presented certificate, it pairs well with other tools on this site for a broader picture. For example, the WHOIS lookup shows registration details of the domain, the DNS lookup shows records that might point to a different server, and the domain age checker gives context on the domain's history. If you need to verify multiple hosts at once, the bulk domain checker may be more efficient. The SSL checker answers one question cleanly: what certificate is this host offering right now?
Frequently Asked Questions
What is an SSL certificate?
An SSL certificate encrypts data between a web server and browser, enabling HTTPS. It verifies the site's identity and protects sensitive information.
How do I check if a website has SSL?
Look for a padlock icon and "https://" in your browser. Use an SSL checker tool for detailed certificate information including issuer and validity.
What's the difference between DV, OV, and EV certificates?
DV verifies domain ownership only. OV also verifies the business. EV requires the most rigorous verification and formerly showed a green address bar.
Are free SSL certificates secure?
Yes. Free certificates from Let's Encrypt provide the same encryption as paid ones. The difference is validation level and support, not security.