CSR Decoder
Decode a Certificate Signing Request.
Runs entirely in your browser — nothing you enter is uploaded, logged, or tracked.
Before you send a Certificate Signing Request to a CA, decode it to confirm it asks for exactly what you intend — the subject (CN, O, …), the public-key type and size, the signature algorithm, and any requested Subject Alternative Names. It is parsed locally in your browser; the CSR never leaves your device.
Frequently asked questions
What is a CSR?
A PKCS#10 Certificate Signing Request — the file you generate and send to a Certificate Authority to request a TLS certificate. It contains your subject details and public key, signed by your private key.
What does the decoder show?
The subject, public-key algorithm and size, signature algorithm, and any requested SANs from the CSR’s attributes/extensions.
Is my CSR uploaded?
No — it is parsed entirely in your browser. A CSR contains only public information, but there is no reason to send it to a third party.