Confirm whether a website serves a working, trusted HTTPS connection.
Browsers do not expose raw certificate fields to JavaScript, so this tool verifies HTTPS reachability and trust by attempting a live secure connection via a CORS relay, rather than reading certificate internals directly.
SSL Certificate Checker tests whether a website can complete a fully trusted HTTPS handshake — the same process your browser performs every time it shows the padlock icon. It gives you a quick pass/fail signal on whether visitors will see a secure connection or a security warning.
Modern browsers deliberately do not expose low-level TLS certificate fields (issuer, exact expiry date, subject alternative names, cipher suite) to JavaScript running on a web page — this is a security boundary, not a limitation of this tool. What this checker can do, entirely client-side, is attempt a live secure request to the target domain through a transparent relay and report whether the handshake succeeded and what HTTP status came back. A successful result means the certificate chain is valid and trusted by standard root authorities; a failure typically means an expired, self-signed, or misconfigured certificate, or that HTTPS isn't supported at all.
Since 2018, Chrome and other major browsers flag any page served without HTTPS as "Not Secure", which erodes visitor trust instantly. Search engines also use HTTPS as a lightweight ranking signal. Beyond appearances, HTTPS encrypts data in transit, protecting login credentials, payment details and session cookies from interception on shared or untrusted networks.
A failed check usually points to one of a few root causes: the certificate has expired and needs renewal, the certificate doesn't match the domain name it's being served on, an intermediate certificate is missing from the server's chain, or the server is misconfigured to serve HTTP only. Most managed hosts and services like Let's Encrypt automate renewal, so a failure is often a sign that automatic renewal broke silently and needs manual attention.
Not directly — browsers block JavaScript from reading raw certificate fields. For that level of detail, use a dedicated certificate inspector such as SSL Labs' server test, which performs a full protocol-level analysis outside the browser sandbox.
If you've previously visited the site, your browser may have cached a trust exception, or the failure may be caused by the specific relay path used for this check rather than a genuine certificate problem — try the direct SSL Labs test to cross-verify.
It confirms the handshake and certificate trust chain are valid, but it doesn't check for weak cipher suites, mixed content, or outdated TLS versions — those require a deeper protocol-level scan.
For internal tools and testing it's fine, but for any public-facing website a self-signed certificate will trigger browser warnings for every visitor and should be replaced with one from a trusted certificate authority.
Most free certificates (like Let's Encrypt) are valid for 90 days and are designed to auto-renew; commercial certificates typically run 1 year. Either way, automated renewal monitoring is strongly recommended.
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