What is SAN in a certificate?
Subject Alternative Name lists domains the certificate is valid for. Modern browsers rely on SAN more than legacy Common Name.
SSL Certificate Decoder
DevTools SSL Certificate Decoder parses certificates, CSRs, and PEM text locally in your browser—view issuer, subject, SAN, validity, and chain details for HTTPS troubleshooting.
SSL Certificate Decoder
Parse SSL certificates, CSRs, and PEM content—view issuer, SAN, validity, and chain details.
About this tool
When deploying HTTPS or fixing cert errors, you need CN, SAN, chain, and expiry quickly. Paste PEM content to inspect fields without openssl on the command line.
How to use
- Paste PEM certificate or CSR text.
- Review auto-parsed fields.
- Check issuer, SAN, validity, and related details.
FAQ
Why do I get errors though the cert is not expired?
Common causes: hostname mismatch, incomplete chain, missing intermediate, wrong system time, or the server still serving an old cert.
Is my certificate uploaded?
No. Parsing runs locally in your browser.
Does it support CSR parsing?
Yes. Paste CSR PEM to inspect subject and public key details.
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