X.509 Certificate Decoder

Decode PEM SSL/TLS certificates and chains: subject, issuer, validity, SANs, key usage and SHA-256 fingerprints. Free and fully in-browser.

About this tool

Decode PEM X.509 certificates and certificate chains. See subject, issuer, validity, subject alternative names, key type and size, key usage and SHA-256/SHA-1 fingerprints.

How to use

Paste one or more PEM certificates (-----BEGIN CERTIFICATE-----) or raw Base64.
Each certificate in the chain is shown in its own table.
Check expiry and copy fingerprints.

Frequently asked questions

Can I paste a private key?

Do not. Only the certificate is needed, and private keys should never be pasted into websites.

How do I get a site's certificate?

Run openssl s_client -connect example.com:443 -showcerts and copy the PEM blocks.

Does it check revocation or trust?

No. It decodes the certificate contents only.

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