Certline opens a TLS connection, reads the certificate the server actually presents, and reports in plain language: the expiry date and days remaining, who issued it, every hostname the certificate covers, and whether the server sent its intermediate.
Check a certificateA certificate can be valid and the site still break, because the server sends the leaf without its intermediate. Desktop browsers paper over it from cache and mobile clients do not. That failure is invisible to anyone looking only at the expiry date, and it is the one people lose a weekend to.
Exact expiry date and days remaining. Know which certificate expires first without logging into every server.
Detects missing intermediates that desktop browsers silently paper over. If the server does not send its intermediate, you see that — not a green padlock on your own machine.
Who issued the certificate and to whom. Full distinguished name fields — organisation, common name, country.
Every hostname the certificate covers. See at a glance whether a wildcard covers your subdomain or a specific SAN is missing.
Number of certificates in the chain and the SHA-256 fingerprint of the leaf. Useful for verifying that the right certificate is deployed.