Decode certificates and check a live host's certificate

Paste a PEM certificate, certificate chain or certificate signing request into the Certificate & CSR decoder to see its subject, alternative names, issuer, validity dates, key type and size, and fingerprints.

Choose Check a live host to retrieve and decode the certificate a server presents. You'll see whether it covers the hostname, when it expires, and whether the server leaves out intermediate certificates. Common TLS ports such as 443, 993 and 8443 are supported.