Check CSR
Validate your CSR format, inspect key type and strength, and check whether Subject Alternative Names (SANs) are included before submitting to a CA.
About Check CSR
The CSR Checker is a free online tool that verifies and displays the contents of a Certificate Signing Request (CSR). A CSR is a block of encoded text that you generate on your server and submit to a Certificate Authority (CA) to request an SSL certificate. Before submitting, it is essential to verify that the CSR contains the correct information.
Errors in a CSR — wrong domain name, incorrect organization details or missing SANs — will result in a certificate being issued with incorrect information that may not work on your server or protect the intended domains.
How to Check a CSR
- Copy your PEM-encoded CSR (-----BEGIN CERTIFICATE REQUEST-----)
- Paste it into the input field
- Click Verify CSR
- Review all decoded fields for accuracy
What Gets Verified
- Common Name (CN) — must match the domain you are securing
- Organization (O) — your company name (for OV/EV certificates)
- Subject Alternative Names (SANs) — additional domains to be protected
- Key size — minimum 2048-bit RSA or 256-bit EC recommended
- Signature algorithm — SHA-256 minimum
If the CSR details look correct, proceed to submit it to your chosen CA. Use our CSR Generator if you need to create a new CSR. Both tools are free with no login required.