Are my private keys or certificates sent to a server?

No. The decoder executes strictly in your browser using client-side ASN.1 parsing and WebCrypto algorithms. Private keys and certificates never leave your machine.

What are Subject Alternative Names (SANs)?

SANs specify all hostnames, wildcard domains (*.domain.com), and IP addresses protected under a single SSL/TLS certificate.

X.509 Certificate & CSR Inspector ASN.1 Parser

Inspect SSL certificates, certificate requests (CSRs), SANs, validity dates, and fingerprints in real-time.

PASTE PEM CERTIFICATE OR CSR

Subject (Issued To)

Common Name (CN): -

Organization (O): -

Country (C): -

Subject Alt Names (SANs): -

Issuer (Certificate Authority)

Common Name (CN): -

Organization (O): -

Country (C): -

Validity Period

Issued (Not Before): -

Expires (Not After): -

Serial Number: -

Cryptographic Details

Public Key Algorithm: -

SHA-256 Fingerprint: -

SHA-1 Fingerprint: -

Frequently Asked Questions

Can this tool parse intermediate and root CA certificates?

Yes. It decodes all standard X.509 v3 certificates, whether they are self-signed root CAs, intermediates, or leaf server certificates.

Does inspecting my certificates trigger any telemetry?

Zero telemetry. All parsing takes place within your browser's execution thread with zero network requests.