CSR Parser API Reference

Overview

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

Endpoint

One host, one path per API. The block below shows this call in four languages; every one of them is the same HTTP request. Making requests covers the timeouts, retries and parameter rules that apply to all of them. The SDKs wrap the same call in a typed client.

POSThttps://api.apiverve.com/v1/csrparser

curl -X POST https://api.apiverve.com/v1/csrparser \
  -H "x-api-key: your_api_key_here" \
  -H "Content-Type: application/json" \
  -d '{
  "csr": "-----BEGIN CERTIFICATE REQUEST-----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\nrJCMi+GypGf9xQUfCJBhTDQVQ3fmCKTfddDeeVbJBrA=\n-----END CERTIFICATE REQUEST-----"
}'

const res = await fetch('https://api.apiverve.com/v1/csrparser', {
  method: 'POST',
  headers: {
    'x-api-key': 'your_api_key_here',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
  "csr": "-----BEGIN CERTIFICATE REQUEST-----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\nrJCMi+GypGf9xQUfCJBhTDQVQ3fmCKTfddDeeVbJBrA=\n-----END CERTIFICATE REQUEST-----"
}),
});

if (!res.ok) throw new Error(`${res.status} ${await res.text()}`);

const { data } = await res.json();
console.log(data);

import requests

res = requests.post(
    "https://api.apiverve.com/v1/csrparser",
    headers={"x-api-key": "your_api_key_here"},
    json={
    "csr": "-----BEGIN CERTIFICATE REQUEST-----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\nrJCMi+GypGf9xQUfCJBhTDQVQ3fmCKTfddDeeVbJBrA=\n-----END CERTIFICATE REQUEST-----"
},
    timeout=15,
)
res.raise_for_status()

print(res.json()["data"])

package main

import (
	"fmt"
	"io"
	"net/http"
	"strings"
)

func main() {
	body := strings.NewReader(`{
  "csr": "-----BEGIN CERTIFICATE REQUEST-----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\nrJCMi+GypGf9xQUfCJBhTDQVQ3fmCKTfddDeeVbJBrA=\n-----END CERTIFICATE REQUEST-----"
}`)
	req, _ := http.NewRequest("POST", "https://api.apiverve.com/v1/csrparser", body)
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("x-api-key", "your_api_key_here")

	res, err := http.DefaultClient.Do(req)
	if err != nil {
		panic(err)
	}
	defer res.Body.Close()

	out, _ := io.ReadAll(res.Body)
	fmt.Println(string(out))
}

Replace your_api_key_here with the key from your dashboard. When the inputs arrive as a list rather than one at a time, batch requests run up to 200 of them through this same API in a single call.

Authentication

Send your key in the x-api-key header. That is the only auth step — there is no token exchange and no per-endpoint scope to configure. Authentication covers creating, rotating and revoking keys.

401 is the only auth verdict

A 401 means the key is missing, invalid or expired. A 403 means the key is valid but not permitted here — blocked by a key restriction or an IP allow-list. Running out of credits is a 429.

Parameters

Sent as JSON in the request body. Premium parameters are accepted on every plan but only take effect on plans that include them.

Parameter	Type	Description
`csr`Required	string	The PEM-formatted Certificate Signing Request to parse

Response

Every API returns the same three top-level keys, so one response handler covers your whole integration: status, error and data. Only data changes shape. Response format covers the envelope, the other output formats and how premium fields are withheld.

Sample response

{
  "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-----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\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"
    }
  }
}

Response fields

Paths are relative to data. Premium fields are absent rather than zeroed on plans that do not include them, so check for presence instead of comparing to 0.

Field	Type	Example	Description
`version`	string	`"v1"`	CSR format version identifier
`subject`	object	`{...}`
`common_name`	string	`"example.com"`	Common name from CSR subject distinguished name
`organization`	string	`"Example Co"`	Organization name from CSR subject field
`organizational_unit`	string	`"DevTeam"`	Organizational unit from CSR subject
`locality`	string	`"San Francisco"`	Locality or city from CSR subject
`state`	string	`"California"`	State or province from CSR subject
`country`	string	`"US"`	Country code from CSR subject
`email`	object	`null`	Email address from CSR subject
`public_key`	object	`{...}`
`algorithm`	string	`"RSA"`	Public key algorithm type used in CSR
`size_bits`	number	`2048`	Public key size in bits
`exponent`Premium	number	`65537`	RSA public exponent value
`signature_algorithm`Premium	string	`"SHA256withRSA"`	Algorithm used to sign the CSR
`extensions`Premium	array	`[]`	X.509 extensions included in CSR
`fingerprints`Premium	object	`{...}`	CSR fingerprints in various hash formats
`sha1`Premium	string	`"05:E5:65:28:8A:47:01:D3:05:EA:3B:3F:F5:DC:C7:42:BF:06:E2:5F"`	SHA1 fingerprint of CSR in colon format
`sha256`Premium	string	`"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"`	SHA256 fingerprint of CSR in colon format
`md5`Premium	string	`"27:C7:EC:94:73:34:E3:B7:3F:F6:FD:3E:0A:81:EA:3D"`	MD5 fingerprint of CSR in colon format
`pem`	string	"-----BEGIN CERTIFICATE REQUEST----- MIICvDCCAaQCAQAwdzELMAkGA1UEBhMCVVMxEzARBgNVBAgMCkNhbGlmb3JuaWEx FjAUBgNVBAcMDVNhbiBGcmFuY2lzY28xEzARBgNVBAoMCkV4YW1wbGUgQ28xEDAO BgNVBAsMB0RldlRlYW0xFDASBgNVBAMMC2V4YW1wbGUuY29tMIIBIjANBgkqhkiG 9w0BAQEFAAOCAQ8AMIIBCgKCAQEAjd/RepiCLQ5/HfKynijcPdiwygrSgxQeTKPo T/WiEaRTaUToW9uDUeiIHK83Tgn2+TIONpMoLJRNG+zslpHybWhVVWNlamkrlRwP XFQJzsxDN5+TQugILatLsp680SgMNyyPtDIpT3niiNuQ4NFepQLvQTbjXgj1celb U86CCeJzYengTF0ZE9Ra+/SsRTA+oy0fNLChNMc2DBaybccxwV2rNWvlvPdhfB7M sel3sw/x2hsbWoYC/kudzYmoDPZKX+XOhCkFwUgwib8V4hbjVLcOYsPBJcROYpRh 9d5g7xdRlbF1I7dHsCRKnsvkIONtwKQmJ2v/UPqYahjtm2TPUQIDAQABoAAwDQYJ KoZIhvcNAQELBQADggEBAFEHOsN2SkB3qFBMk9JR5IDoh8rSUKj/310DOwilOQm+ 5lAwRfcFMYCl9yf4IV+XPPfvT3ahzUFfi8Fc98CDeIxAhEwtuZFlE7LA5+/F4HXM H3gzqTFwOZq+Wa2m029/BvcyII830h4Z+gU68R52px7O7wYSbAR/n7t1fh2bxzmW KqqjrvCpHoMVpgcm9y2bYTj+HLxgX4/uADFvotQppOWZi0ctam+if3Kqb3Kd2MFD vVHZp9NwEoqNPxmFEzcyOk2y1PYhhRja7rjdC6bdAqj6JRt+WSzStvgx7aEsxBQj rJCMi+GypGf9xQUfCJBhTDQVQ3fmCKTfddDeeVbJBrA= -----END CERTIFICATE REQUEST-----"	PEM-encoded CSR data
`size_bytes`	number	`704`	CSR size in bytes
`format`	string	`"PEM"`	Certificate encoding format type
`is_valid`	boolean	`true`	Whether CSR format is valid
`security_assessment`Premium	object	`{...}`	Derived security posture of the request: weak-key detection (RSA < 2048 / EC < 256), deprecated signature hash (SHA1/MD5), and an overall key strength rating
`is_weak_key`Premium	boolean	`false`
`is_deprecated_signature`Premium	boolean	`false`
`key_strength`Premium	string	`"acceptable"`

Errors

Read the HTTP status first, then error for the specific reason. The body names the parameter that has to change. Error handling covers the full status list and which of them are worth retrying.

Status	Meaning	What to do
`400`	Input was rejected	Read `error`; it names the parameter.
`401`	Key missing or invalid	Check the header name and the key value.
`403`	Key valid, but not permitted	A key restriction or IP allow-list; see key scoping.
`429`	Rate limited, or out of credits	Read `error` to tell them apart; see rate limits.

Use cases

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

Other ways to use CSR Parser

Set up CSR Parser on APIVerve, or reach the same source a different way. Your APIVerve account and credits work on all of them — one key, one balance.

Give it to an AI agentConnect over MCP and your agent calls it as a native tool — Claude, Cursor, ChatGPT.VerveKit →Reference →

CSR Parser