PEM Decoder
Decode PEM-encoded X.509 certificates and view subject, issuer, validity, and SANs – client-side only
Paste PEM content below or drop a .pem / .crt file here. Decoding runs entirely in your browser; nothing is sent to any server.
Decoding happens entirely in your browser. Your certificate or key material is never sent to our servers.
PEM Decoder
This free PEM decoder parses PEM-encoded X.509 certificates and shows subject, issuer, validity dates, subject alternative names (SANs), serial number, and signature algorithm. Paste PEM content or upload a .pem or .crt file. Decoding runs entirely in your browser; no certificate data is sent to any server.
What you get
- Subject – Common Name (CN), Organization (O), and other DN fields
- Issuer – Certificate authority that signed the cert
- Validity – Not Before, Not After, and whether the cert is valid, expired, or not yet valid
- Subject Alternative Names (SANs) – DNS names and IP addresses
- Serial number and signature algorithm
Use cases
- DevOps and TLS – Inspect server or client certificates without command-line tools
- Security reviews – Check expiry and SANs before or after deployment
- Chains – Paste multiple certificates (e.g. full chain) to decode each one
For decoding JSON Web Tokens, use the JWT Decoder. For hashing text or files, try the Hash Generator.