What does a CSR checker verify?

A CSR (Certificate Signing Request) checker decodes and validates the CSR file you submit to a certificate authority. It shows the common name (domain), organisation, country, key algorithm, key size, and any Subject Alternative Names included in the request.

What key size should I use when generating a CSR?

A minimum of 2048-bit RSA is required by most certificate authorities today. 4096-bit RSA provides stronger security at the cost of slightly slower TLS handshakes. Elliptic Curve keys at 256 bits offer equivalent security to 3072-bit RSA with better performance.

Can I reuse a CSR for certificate renewals?

Technically yes, but it is best practice to generate a new CSR and new private key for each certificate renewal. Reusing a private key means that if the old key was ever compromised, the new certificate inherits that vulnerability.

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Check CSR

Paste a Certificate Signing Request to validate it and inspect all fields — domain, organisation, key type, key size and Subject Alternative Names.

Frequently Asked Questions

What is a CSR?

A Certificate Signing Request (CSR) is a block of encoded text submitted to a Certificate Authority. It contains your public key and domain information. The CA uses it to issue the certificate.

What should I check in a CSR?

Check that the Common Name (CN) exactly matches the domain you want to secure. Verify the key size is at least 2048 bits for RSA. Make sure the organisation and country fields are correct before submitting to a CA.

What is a SAN entry?

Subject Alternative Names (SANs) allow a single certificate to cover multiple domains. Modern CSRs should include SAN entries rather than relying only on the CN. Most CAs now require at least one SAN matching the CN.

Related: All SSL Tools CSR Generator CSR Decoder SSL Checker Key Matcher