X.509 Certificate Parser
Paste PEM certificate (or pure base64 DER), parse subject, issuer, validity, serial number, public key / signature algorithm, SHA-1 / SHA-256 fingerprint. Pure browser-side ASN.1 parsing; certificates never uploaded.
SAML Scenario
The <ds:X509Certificate> content in SAML Metadata is base64 DER that can be pasted directly here to view IdP/SP signing certificate info and validity.