CSR Decoder API

Decode a PKCS#10 certificate signing request: subject, public key, requested SANs and extensions, attributes, and whether its self-signature is valid.

POST /api/v1/tools/csr-decoderMCP csr_decoderSecurity & Privacy

Decode a PKCS#10 certificate signing request to check its subject, SANs, key type and size, then verify its signature. Runs in your browser, nothing is uploaded.

Input

Send these as a JSON object. Unknown fields are rejected.

pem: The CSR in PEM format (-----BEGIN CERTIFICATE REQUEST-----) or base64 DER. (string, up to 50000 characters, required)

Try it in the browser JSON Schema Get an API key

curl https://pithlab.com/api/v1/tools/csr-decoder \n  -H "Authorization: Bearer $PITHLAB_KEY" \n  -H "Content-Type: application/json" \n  -d '{"pem":"-----BEGIN CERTIFICATE REQUEST-----\nMIIBzzCCAXYCAQAwgZExCzAJBgNVBAYTAkdCMQ8wDQYDVQQIDAZMb25kb24xDzAN\nBgNVBAcMBkxvbmRvbjEUMBIGA1UECgwLRXhhbXBsZSBMdGQxDDAKBgNVBAsMA1dl\nYjEZMBcGA1UEAwwQd3d3LmV4YW1wbGUudGVzdDEhMB8GCSqGSIb3DQEJARYSYWRt\naW5AZXhhbXBsZS50ZXN0MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEWIxfVoyp\n0KgIZ3n+X+yyE91ZT/rmpCkycrF/J+R5JFfYL0+3tnlR9wE9ZyHH1jQhY6vkSOw0\nwd/aUHga4HN3/qCBgTB/BgkqhkiG9w0BCQ4xcjBwMG4GA1UdEQRnMGWCEHd3dy5l\neGFtcGxlLnRlc3SCDGV4YW1wbGUudGVzdIcEwAACCocQIAENuAAAAAAAAAAAAAAA\nAYESYWRtaW5AZXhhbXBsZS50ZXN0hhdodHRwczovL2V4YW1wbGUudGVzdC9pZDAK\nBggqhkjOPQQDAgNHADBEAiBIAlGjvPhfb3QjhVHOSmSli1Surh1qzrnkG1kl5L3g\nKAIgZD5i+6FmSB3FkqdOJZ/Ka3xK2grhF0jV+owHocoukgw=\n-----END CERTIFICATE REQUEST-----\n"}'

Example response

{
  "ok": true,
  "result": {
    "subject": "C = GB, ST = London, L = London, O = Example Ltd, OU = Web, CN = www.example.test, emailAddress = [email protected]",
    "publicKey": {
      "type": "EC",
      "description": "EC P-256 (prime256v1)",
      "bits": 256,
      "curve": "P-256 (prime256v1)"
    },
    "signatureAlgorithm": "ecdsa-with-SHA256",
    "signatureValid": true,
    "signature": "Valid: the request was signed by the private key matching its public key",
    "extensions": {
      "all": [
        {
          "oid": "2.5.29.17",
          "name": "subjectAltName",
          "critical": false
        }
      ],
      "subjectAltNames": [
        {
          "type": "DNS",
          "value": "www.example.test"
        },
        {
          "type": "DNS",
          "value": "example.test"
        },
        {
          "type": "IP",
          "value": "192.0.2.10"
        },
        {
          "type": "IP",
          "value": "2001:db8::1"
        },
        {
          "type": "email",
          "value": "[email protected]"
        },
        {
          "type": "URI",
          "value": "https://example.test/id"
        }
      ]
    },
    "attributes": []
  }
}