HMAC-SHA512

All transactional requests (cash-out, cash-in, refund) require an HMAC-SHA512 signature to ensure integrity and authenticity.

How It Works

1. Serialize the request body as JSON
2. Generate the HMAC-SHA512 signature using your client_secret as the key
3. Send the signature in the hmac header

Required Headers

Header	Value
Authorization	Bearer {access_token}
Content-Type	application/json
hmac	HMAC-SHA512 signature in hexadecimal

Examples

JavaScript (Node.js)

const crypto = require('crypto');

const body = JSON.stringify({
  amount: 10000,
  pix_key: "12345678901",
  description: "Payment"
});

const hmac = crypto
  .createHmac('sha512', 'your-api-key-secret')
  .update(body)
  .digest('hex');

// Send as header: hmac: {value}

Python

import hmac
import hashlib
import json

body = json.dumps({
    "amount": 10000,
    "pix_key": "12345678901",
    "description": "Payment"
})

signature = hmac.new(
    b"your-api-key-secret",
    body.encode("utf-8"),
    hashlib.sha512
).hexdigest()

PHP

$body = json_encode([
    'amount' => 10000,
    'pix_key' => '12345678901',
    'description' => 'Payment'
]);

$hmac = hash_hmac('sha512', $body, 'your-api-key-secret');

Java

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;

String body = "{\"amount\":10000,\"pix_key\":\"12345678901\",\"description\":\"Payment\"}";
String secret = "your-api-key-secret";

Mac mac = Mac.getInstance("HmacSHA512");
SecretKeySpec keySpec = new SecretKeySpec(secret.getBytes(), "HmacSHA512");
mac.init(keySpec);
byte[] hash = mac.doFinal(body.getBytes());

StringBuilder sb = new StringBuilder();
for (byte b : hash) {
    sb.append(String.format("%02x", b));
}
String hmac = sb.toString();

C#

using System.Security.Cryptography;
using System.Text;

var body = "{\"amount\":10000,\"pix_key\":\"12345678901\",\"description\":\"Payment\"}";
var secret = Encoding.UTF8.GetBytes("your-api-key-secret");

using var hmacSha512 = new HMACSHA512(secret);
var hash = hmacSha512.ComputeHash(Encoding.UTF8.GetBytes(body));
var hmac = BitConverter.ToString(hash).Replace("-", "").ToLower();

Bash (curl)

BODY='{"amount":10000,"pix_key":"12345678901","description":"Payment"}'
SECRET="your-api-key-secret"

HMAC=$(echo -n "$BODY" | openssl dgst -sha512 -hmac "$SECRET" | awk '{print $2}')

curl -X POST https://api.owem.com.br/api/v2/external/pix/cash-out \
  -H "Authorization: Bearer $TOKEN" \
  -H "Content-Type: application/json" \
  -H "hmac: $HMAC" \
  -d "$BODY"

Validation

The API validates the received HMAC against the request body. If the signature does not match:

{
  "worked": false,
  "detail": "Invalid HMAC"
}

Important

• Use the body exactly as sent in the request (same JSON serialization)
• The API Key client_secret is the HMAC key
• The signature must be in lowercase hexadecimal format