Inspect PEM X.509 certificates: subject, validity, SANs, fingerprint — parsed locally.
Inspect PEM X.509 certificates: subject, validity, SANs, fingerprint — parsed locally.
Certificate Decoder
Load a PEM certificate to inspect subject, issuer, validity window, signature algorithm, Subject Alternative Names, and SHA-256 fingerprint — parsed locally.
Certificate Decoder Use Cases
- Quickly read SANs and expiry during incidents
- Compare dev vs prod cert metadata
- Document handshake issues with precise fingerprints
- Teach X.509 structure without openssl installed
Certificate Decoder FAQ
Does this validate trust chains?
It parses and displays fields. Full chain validation against trust stores is out of scope for this lightweight viewer.
Why two fingerprint styles?
We show SHA-256 as colon-separated hex, a common admin format.
Can I paste DER?
The decoder accepts PEM and common encodings supported by the parser; PEM with headers is the easiest path.
Is the certificate uploaded?
No. Parsing happens entirely in your browser.