How to use the ssl certificate checker
- Enter the domain (or paste the site's URL) and press Check certificate.
- Read the verdict banner first: it tells you if the certificate is expired, not yet valid, issued for a different name, or not trusted.
- Check the days remaining and set a reminder if renewal is close; many certificates now last only 90 days.
- Look at the covered names to confirm both the bare domain and www are included, and at the chain to spot a missing intermediate.
Features
- Verdict on validity, hostname match and trust, with the exact reason when something is wrong
- Days remaining with a warning at 14 days, plus precise valid-from and valid-until times
- Issuer, subject, serial number, SHA-256 fingerprint and every Subject Alternative Name
- The chain exactly as the server presents it, so a missing intermediate is visible
- Negotiated TLS protocol, cipher suite and key type
What the checks mean
A certificate proves that the party you connect to controls the domain. Browsers verify three things: the current time is inside the validity window, the requested hostname appears in the certificate's names, and the chain leads to a root the browser trusts. This tool performs the same checks from VoltKit's server.
A chain problem is the most common cause of 'works on my laptop, fails on phones': the server omits an intermediate certificate that desktop browsers happen to have cached. The chain section shows exactly what was sent.
Limits of a remote check
The check connects to port 443 with your domain as the server name (SNI) from VoltKit's hosting region. Sites that serve different certificates by region or by client, or that block automated connections, may show something different from what your browser sees. Trust is evaluated against the server's root store, which is very close to, but not identical to, each browser's.