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Online Certificate Decoder

Paste a certificate, upload a file, or point at a live server to see every field in plain language — subject, issuer, SANs, validity, key details and fingerprints.

Paste one certificate, several concatenated PEM blocks, or upload a .pem/.crt/.cer/.der file.

Equivalent OpenSSL command

openssl x509 -in certificate.pem -noout -text -fingerprint -sha256

Runs entirely in your browser. Certificates, keys and passwords you enter here are processed locally with JavaScript and are never uploaded or sent to any server — nothing is stored, logged or transmitted.