SSL Tools · CSR Decoder
Make sure your CSR says what you think it says
Check what a CSR really contains before you hand it to a certificate authority - a typo here costs a reissue.
- Free
- No sign-up
- Nothing you paste is stored
Paste a certificate signing request and read back exactly what is inside it. Worth thirty seconds before you hand a CSR to a certificate authority - a wrong common name means a reissue.

Check these before you order
- Common name - the exact host name, including or excluding www as you intend
- Organisation and country - must match your registration documents for OV and EV
- Key size - 2048 bits is the minimum any authority will accept
- Signature algorithm - SHA-2; SHA-1 has not been accepted for years
What a CSR is
A certificate signing request is a small encoded block your server generates alongside a private key. It carries the details you want on the certificate - host name, organisation, location - and your public key. The authority signs it and hands back a certificate. The private key never leaves your server, which is why a CSR is safe to email and a private key is not.
Why decoding it first saves a day
Authorities validate against what is in the CSR, not what you meant to type. A typo in the common name, a missing organisation unit or a country code that does not match your paperwork all lead to the same place: a rejected order or a certificate you cannot use, and a reissue that starts validation again.
Other tools
All seven →- SSL Checker Is the certificate installed, trusted, and served with the right chain?
- Check SSL Read the issuer, expiry date and covered names off any live site.
- Certificate Decoder Paste a certificate and read what is actually inside it.
- CSR Generator Build a certificate signing request without touching OpenSSL.
- Key Matcher Confirm a certificate, its CSR and its private key belong together.
- Server Checker What software your server runs, and which protocols it accepts.
Found a problem you would rather not fix yourself?
Send us the domain and the error. Our engineers install and troubleshoot certificates on any platform we sell for.