CSR Parser API

POST

Inspect CSRs and extract key details before issuing certificates.

CSR Parser extracts and analyzes information from Certificate Signing Requests (CSRs), providing detailed subject information, public key details, and fingerprints.

Try it — live request, no key required

Request
POSTapi.apiverve.com/v1/csrparser
Body
Verification
Format

No key required to try it. Get a key to use it in your app.

Example
{
  "status": "ok",
  "error": null,
  "data": {
    "version": "v1",
    "subject": {
      "common_name": "example.com",
      "organization": "Example Co",
      "organizational_unit": "DevTeam",
      "locality": "San Francisco",
      "state": "California",
      "country": "US",
      "email": null
    },
    "public_key": {
      "algorithm": "RSA",
      "size_bits": 2048,
      "exponent": 65537
    },
    "signature_algorithm": "SHA256withRSA",
    "extensions": [],
    "fingerprints": {
      "sha1": "05:E5:65:28:8A:47:01:D3:05:EA:3B:3F:F5:DC:C7:42:BF:06:E2:5F",
      "sha256": "E0:0B:C1:59:A3:9E:F9:96:13:7B:CE:98:BC:8F:A1:49:62:4D:2E:CF:85:D5:36:2C:DD:46:9E:96:CF:92:A3:AF",
      "md5": "27:C7:EC:94:73:34:E3:B7:3F:F6:FD:3E:0A:81:EA:3D"
    },
    "pem": "-----BEGIN CERTIFICATE REQUEST-----\nMIICvDCCAaQCAQAwdzELMAkGA1UEBhMCVVMxEzARBgNVBAgMCkNhbGlmb3JuaWEx\nFjAUBgNVBAcMDVNhbiBGcmFuY2lzY28xEzARBgNVBAoMCkV4YW1wbGUgQ28xEDAO\nBgNVBAsMB0RldlRlYW0xFDASBgNVBAMMC2V4YW1wbGUuY29tMIIBIjANBgkqhkiG\n9w0BAQEFAAOCAQ8AMIIBCgKCAQEAjd/RepiCLQ5/HfKynijcPdiwygrSgxQeTKPo\nT/WiEaRTaUToW9uDUeiIHK83Tgn2+TIONpMoLJRNG+zslpHybWhVVWNlamkrlRwP\nXFQJzsxDN5+TQugILatLsp680SgMNyyPtDIpT3niiNuQ4NFepQLvQTbjXgj1celb\nU86CCeJzYengTF0ZE9Ra+/SsRTA+oy0fNLChNMc2DBaybccxwV2rNWvlvPdhfB7M\nsel3sw/x2hsbWoYC/kudzYmoDPZKX+XOhCkFwUgwib8V4hbjVLcOYsPBJcROYpRh\n9d5g7xdRlbF1I7dHsCRKnsvkIONtwKQmJ2v/UPqYahjtm2TPUQIDAQABoAAwDQYJ\nKoZIhvcNAQELBQADggEBAFEHOsN2SkB3qFBMk9JR5IDoh8rSUKj/310DOwilOQm+\n5lAwRfcFMYCl9yf4IV+XPPfvT3ahzUFfi8Fc98CDeIxAhEwtuZFlE7LA5+/F4HXM\nH3gzqTFwOZq+Wa2m029/BvcyII830h4Z+gU68R52px7O7wYSbAR/n7t1fh2bxzmW\nKqqjrvCpHoMVpgcm9y2bYTj+HLxgX4/uADFvotQppOWZi0ctam+if3Kqb3Kd2MFD\nvVHZp9NwEoqNPxmFEzcyOk2y1PYhhRja7rjdC6bdAqj6JRt+WSzStvgx7aEsxBQj\nrJCMi+GypGf9xQUfCJBhTDQVQ3fmCKTfddDeeVbJBrA=\n-----END CERTIFICATE REQUEST-----",
    "size_bytes": 704,
    "format": "PEM",
    "is_valid": true,
    "security_assessment": {
      "is_weak_key": false,
      "is_deprecated_signature": false,
      "key_strength": "acceptable"
    }
  }
}

About the CSR Parser API

Perfect for SSL/TLS certificate management systems, security tools, and automated certificate workflows that need to validate and process CSRs.

What people use it for

CSR Validation
Validate Certificate Signing Requests before certificate issuance to ensure proper formatting and required fields
Information Extraction
Extract subject information, public key details, and signature algorithms from certificate requests for processing
Certificate Management
Build certificate management systems with automated CSR parsing and validation capabilities
SSL/TLS Automation
Automate SSL/TLS certificate workflows including CSR generation validation, certificate issuance, and renewal processes

Ways to call it

One endpoint, many ways in — REST with JSON, XML, YAML and CSV, plus GraphQL and an MCP interface for AI agents.

JSON
Default REST response
XML
Markup format
YAML
Human-readable
CSV
Tabular export
Beta
GraphQL
Query language
New
MCP
For AI agents

Other ways to use CSR Parser

Same data, same APIVerve account, same credit balance — one key works on all of them.

Questions.

Common questions about the CSR Parser API.

Read the docs →
What format must the Certificate Signing Request be in?
The CSR must be provided as a standard PEM-formatted string. CSR Parser processes the PEM data and confirms whether the structure is valid, returning the version, encoding format, size in bytes, and parsed cryptographic attributes.
Which subject details does CSR Parser extract?
It extracts all standard distinguished name components found in the CSR subject. This includes the common name, organization, organizational unit, locality, state or province, country code, and email address.
Are CSR fingerprints and the security assessment included on the Free plan?
No, those require a paid subscription. The Free plan returns core subject and key attributes, while any paid plan unlocks the security assessment, signature algorithm, X.509 extensions, RSA public exponent, and SHA1, SHA256, and MD5 fingerprints.
Will the parser flag weak keys or deprecated signature algorithms?
Yes, on paid plans. The security assessment identifies weak key sizes, specifically RSA keys under 2048 bits and elliptic curve keys under 256 bits. It also identifies legacy signature hashes such as MD5 and SHA1.
How many CSRs does the Free plan cover?
The Free plan covers 100 CSRs each month, with each request using 2 credits. If you need higher volume for automated workflows, the Starter plan covers up to 100,000 CSRs per month, which works out to about $0.30 per 1,000 calls.

Ready to build with CSR Parser? Start with 200 free credits — one key unlocks all 300+ APIs.

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