CSR decoder

No third-party request

Validate a PKCS#10 self-signature and inspect the requested subject, SANs, extensions, and public key before submitting it to a certificate authority.

Input is capped at 32 KB, processed transiently by this server, and is not logged, cached, saved, or sent to another provider.

Paste a PEM CSR to beginMalformed requests and requests whose embedded public key cannot verify their self-signature are rejected.

What validation does—and does not—prove

A valid PKCS#10 self-signature proves the request has not changed since it was signed by the corresponding private key. It does not prove domain control, organizational identity, or that a certificate authority will accept every requested extension.

A CSR contains a public key, not the private key. Even so, treat infrastructure names and organization details as sensitive configuration and remove the input from shared devices when finished.