What does the SAN list show?

All hostnames the certificate is valid for — useful when one cert covers a domain plus all its subdomains, or multiple unrelated domains.

Most automation (Let's Encrypt, ACME) renews at 30 days remaining. Treat 14 days remaining as an urgent warning, 7 as critical.

What if the cert is invalid?

The tool returns the SSL error message — common causes are expired certificate, self-signed, mismatched hostname, or untrusted CA.

Utilities Tool

Inspect an HTTPS site's TLS certificate — issuer, validity, expiry, SAN list, cipher.

Privacy-first workflows

Fast and simple

100% Free, no signup

Host

Port

How it works

STEP 01

Type the host (example.com) and optionally a non-default port.

STEP 02

Click Check SSL.

STEP 03

Review issuer, subject, expiry countdown, and the list of subject alternative names (SANs).

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FAQ