Check HTTPS certificate expiry, hostname match, trusted chain, TLS version, cipher suite, SAN entries, OCSP stapling, and issuer details for any host.
An SSL/TLS certificate proves that the HTTPS server is presenting a certificate for the hostname you entered and lets browsers encrypt the connection. This SSL certificate checker confirms whether the certificate matches the hostname, it is currently valid (issued in the past and not expired), and it chains to a trusted root in the system trust store.
The chain of trust walks from the leaf certificate for the domain, through one or more intermediate CA certificates, up to a self-signed root . A browser only trusts a site if every link in that certificate chain validates. Short-lived certificates, including many Let's Encrypt certificates, are normal. What matters is that ACME renewal happens before the SSL expiration date.
The connection details also show the negotiated TLS version, cipher suite , key exchange, signature algorithm, Subject Alternative Names, and whether the server stapled an OCSP response during the TLS handshake.
Use this HTTPS certificate checker after changing DNS, moving a site behind a CDN, renewing a certificate, or debugging browser warnings. The most common issues are expired certificates, hostname mismatch errors, missing intermediate certificates, self-signed certificates, and services that do not answer TLS on port 443.
If a hostname mismatch appears, compare the host you entered with the certificate common name and SAN entries. If the certificate chain checker warns, reinstall the full chain from your certificate authority. If the certificate expiry checker shows a short renewal window, verify that your ACME client or hosting provider will renew before the date shown above.
This SSL certificate checker opens a TLS connection to the host on port 443, reads the certificate, checks the hostname match, validity dates, trusted chain, signature strength, TLS protocol, cipher suite, key exchange, SAN entries, and OCSP stapling.
Enter the HTTPS hostname and review the Expires and Days left fields. The certificate expiry checker highlights short renewal windows so you can renew before browsers start showing certificate errors.
A hostname mismatch happens when the certificate common name or Subject Alternative Names do not cover the host you entered. It often appears after pointing DNS to a new service without issuing a matching certificate.
Browsers trust a certificate only when the leaf certificate chains through the required intermediate certificates to a trusted root CA. A missing intermediate certificate can break HTTPS even when the leaf certificate is not expired.
Yes. The connection section reports the negotiated TLS version, cipher suite, key type, key exchange, and whether the server stapled an OCSP response during the handshake.
No. This page focuses on the TLS certificate and HTTPS handshake. Use DNS lookup to check records and a dedicated security headers checker when that tool is available.