X.509 decoder and chain validator that runs in your browser
Your certificate is parsed locally in your browser. Nothing is uploaded to a server, logged, stored, or put in the URL.
PEM, raw Base64, Base64 that wraps a PEM file, hex, DER, a PKCS#7 bundle or a whole chain. The format is detected for you.
Subject, issuer, validity, SANs, key, signature, key usage, basic constraints, fingerprints, every extension, the ASN.1 tree and an openssl-style view.
Certificates are ordered into a chain and each hop is verified: issuer names, AKI/SKI, and the actual signatures.
Generated locally in your browser — no real certificate is involved.