CSR Decoder
Paste any Certificate Signing Request to decode and inspect all fields — domain, organisation, key algorithm, key size, SANs and a security analysis.
Frequently Asked Questions
What is the difference between CSR Decoder and Check CSR?
Both decode CSR fields. CSR Decoder provides a more detailed security analysis including key strength assessment and SAN validation. Check CSR is a quick validity check. Use the decoder when auditing a CSR before submitting to a CA.
What key size should I use?
2048-bit RSA is the current minimum standard. 4096-bit provides stronger security at the cost of slightly slower handshakes. EC (Elliptic Curve) keys at 256-bit offer equivalent security to 3072-bit RSA with better performance.
Why are SAN entries important?
Modern browsers require Subject Alternative Names. A certificate with only a CN and no SAN entries will cause certificate errors in Chrome, Firefox and Edge even if the CN matches. Always include at least one SAN entry matching your domain.