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When it fires

The cash_in event fires when:
  • A SPEI transfer arrives at the disposable CLABE issued by POST /api/spei/cash-in and is settled
  • An OXXO payment issued by POST /api/oxxo/cash-in is paid at the register and confirmed

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Payload

{
  "event": "cash_in",
  "deliveryId": "8e2c5b6f-3a12-4b9c-9a18-77a2b3c4d5e6",
  "createdAt": "2026-05-12T14:31:05.000Z",
  "transaction": {
    "id": 12345,
    "externalId": "order-abc-123",
    "paymentMethod": "SPEI",
    "direction": "in",
    "type": "cash_in",
    "status": "CONFIRMED",
    "provider": "smartfastpay",
    "amountCentavos": 50000,
    "clabe": "012180001234567890",
    "createdAt": "2026-05-12T14:30:00.000Z",
    "confirmedAt": "2026-05-12T14:31:05.000Z"
  }
}

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Headers

HeaderValue
X-NTXPay-Eventcash_in
X-NTXPay-Signaturesha256=<hmac>
X-NTXPay-TimestampUnix epoch (seconds)
X-NTXPay-Deliveryunique delivery UUID

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SPEI vs OXXO Differences

AspectSPEIOXXO
paymentMethodSPEIOXXO
clabeSource CLABEnull
Time to confirmationSeconds to minutesMinutes to hours after paying at register
Additional identifierreferenceNumericalreferenceNumerical

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Expected Response

Respond 200 OK in under 10 seconds. On any other status, NTX Pay retries up to 5 times in exponential backoff. 
HTTP/1.1 200 OK
Content-Type: application/json

{"received": true}

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Handler Example (Node.js / Express)

import express from 'express';
import crypto from 'crypto';

const app = express();
app.use(express.raw({ type: 'application/json' })); // raw body for HMAC

const SECRET = process.env.NTXPAY_WEBHOOK_SECRET!;

app.post('/webhooks/ntxpay', (req, res) => {
  const sig = req.header('X-NTXPay-Signature') ?? '';
  const expected = 'sha256=' + crypto
    .createHmac('sha256', SECRET)
    .update(req.body) // req.body is Buffer
    .digest('hex');

  if (!crypto.timingSafeEqual(Buffer.from(sig), Buffer.from(expected))) {
    return res.status(401).end();
  }

  const event = JSON.parse(req.body.toString());
  if (event.event === 'cash_in' && event.transaction.status === 'CONFIRMED') {
    enqueue(event); // process async
  }

  res.json({ received: true });
});
See the implementation guide for Python and PHP.