Paste a PEM certificate to decode its subject, issuer, validity dates, SANs, key and SHA-256 fingerprint - and check whether it covers your hostname. Runs entirely in your browser.
The SSL Certificate Checker reads any PEM certificate and shows who issued it, who it was issued to, when it becomes valid, when it expires and how many days are left. Paste the certificate from your server, hosting panel or .crt file, type the hostname you want to verify, and the tool checks the Subject Alternative Names against real browser wildcard rules, together with the public key, the signature algorithm, the serial number and the SHA-256 fingerprint. Everything is parsed in your browser, so the certificate is never uploaded and internal or staging certificates stay private. Use it before a renewal to see the remaining days at a glance, or after a deployment to confirm that the certificate installed on the server is really the one you ordered.