SSL Certificate Decoder

Decode a PEM SSL/TLS certificate: domains (SANs), issuer, validity dates, key size and fingerprints.

How do I read the details of an SSL certificate?

Paste the certificate text that starts with -----BEGIN CERTIFICATE----- and the decoder shows who it was issued to, which domains it covers, who issued it, when it expires, the public key size and the SHA-256 fingerprint.

Where to find the certificate

In the .crt or .pem file your certificate authority sent, or your server’s certificate folder.
In the browser: padlock → Certificate → Details → Export.
To check a live website instead, use the SSL Checker.

Certificates are public information, so they are safe to paste. Never paste a private key.

Frequently asked questions

Can it read a certificate chain?

It decodes the first certificate in the text — paste each one separately to inspect intermediates.

What is a SAN?

Subject Alternative Name — the list of domain names the certificate is valid for.

Is the certificate stored?

No, it is decoded and discarded.