An SSL certificate contains information such as domain ownership, issuing authority, validity period and subject alternative names. When troubleshooting HTTPS, checking expiry or verifying certificate chains, being able to decode a certificate quickly is essential.
This SSL Certificate Decoder allows you to paste a PEM, CRT or CER formatted certificate and instantly view the full X.509 details. It extracts the subject, issuer, fingerprints, expiration, public key info and SAN entries so you can inspect everything in readable form.
SSL Certificate Decoder
SSL and TLS certificates are a core part of encrypted web traffic. When something breaks, the fastest way to diagnose is to decode the certificate and check who issued it, which domains it applies to and whether it has expired. This tool saves time by decoding everything automatically without command line tools or complicated scripts.
Use this SSL certificate decoder for:
- Checking certificate expiry dates
- Inspecting SANs and domain coverage
- Validating chain relationships and fingerprints
- Debugging HTTPS handshake issues
- Viewing public key details and metadata
You can decode certificates from servers, email security, VPN configurations or reverse proxies. If you later want HTML export or table output for the fields, tell me and I can generate a structured version ready for pasting into WordPress.