SSL Certificate Decoder & CSR Generator
Decode X.509 PEM certificates and generate CSRs with private keys in your browser. Fast, free, and fully client-side.
Paste X.509 Certificate or CSR
Accepts standard PEM format (-----BEGIN CERTIFICATE----- or -----BEGIN CERTIFICATE REQUEST-----).
How the SSL Certificate Decoder & CSR Generator Works
Decode and inspect SSL/TLS certificates (X.509 PEM/DER) to view Subject, Issuer, Validity Dates, Serial Number, Subject Alternative Names (SANs), and SHA-256 fingerprints. Also includes a client-side Certificate Signing Request (CSR) generator that creates a fresh keypair on your device.
Usage Example
Check when an SSL certificate expires or generate a new RSA/ECDSA keypair and CSR.
Frequently Asked Questions
Are my private keys secure when generating a CSR?
Yes. Private keys are generated entirely in local memory on your device and are never transmitted anywhere.