Safe

X.509 Certificate Decoder

TLS

Parse and inspect X.509 PEM/CRT SSL/TLS certificates client-side: Subject, Issuer, SANs, Validity dates, and Serial numbers.

Zero server interaction — certificate decoding runs entirely within your browser.

Detects expiration status, days remaining, and Subject Alternative Names (SANs).

Paste X.509 Certificate (PEM format)

-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----

Invalid certificate sequence structure

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