Penny Validation API
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Overview

The Penny Validation API enables account ownership verification by sending a minimal payment (penny) to a beneficiary account. This process generates a CEP (Comprobante Electrónico de Pago) that provides verified account holder information and creates an official payment receipt through BANXICO.

Key Benefits

Account Verification: Confirm the actual account holder matches your intended recipient
Official Documentation Get a easy to use URL to obtain a XML or PDF receipts for compliance and record-keeping directly from Banxico's website.
Fraud Prevention: Automate payments, reduce errors and fraudulent transactions

Important Considerations

Processing Time: CEP generation depends on the beneficiary's bank and may vary significantly
Supported Accounts: Currently supports CLABE accounts only (debit card support planned)
Future Enhancements: Automatic webhook notification when CEP is ready

Penny Validation endpoint

Prerequisites You need to have a CENTRALIZING_ACCOUNT and an INSTRUMENT previously created. And you need to create a new webhook for the penny validation message.

Endpoint POST /v1/transactions/penny_validation

Request Path parameters: none

Query Parameters: none

Request Body:

{
    "client_id": "{{client_id}}",
    "source_instrument_id": "", //use your own centralizing account where funds are located
    "destination_instrument_id": "" //add the id of the previously generated instrument
}

Response
Status Code: 200 OK
Response Body:

{
    "id": "1eb4b5ac-71f6-4203-aded-4fcb7fd21637",
    "bankId": "14b402f6-5dd1-4cd8-ac54-d12c5647d137",
    "clientId": "09b1c156-73c7-62e1-9a3e-bf705f8f3cbe",
    "externalReference": "123456",
    "trackingId": "20250820FINCHXXXXQ6RPX4",
    "description": "Validacion de cuenta FINCO_PAY",
    "amount": "0.01",
    "currency": "MXN",
    "category": "DEBIT_TRANS",
    "subCategory": "SPEI_DEBIT",
    "transactionStatus": "INITIALIZED",
    "audit": {
        "createdAt": "2025-08-19 13:03:36.194761-06:00",
        "updatedAt": "2025-08-19 13:03:36.194761-06:00",
        "deletedAt": "None",
        "blockedAt": "None"
    },
    "metadata": {
        "dataCep": {
            "cepUrl": "https://www.banxico.org.mx/cep/go?i=90734&s=20250401&d=uBq%2BmmaxaJx72v%2FafY3P2XgtF6PkNIxovKrCElr14xnUBOcXkfe9Vllu8xJ%2FHNPE6YqJ9U%2F2BEcsd3jbcB8OdTqrcqUZYkYQYxzjg4WIVSg%3D",
            "validationId": "f4ebe9af-6c93-4218-8dcb-74cb7456f3cd",
            "status": "INITIALIZED",
            "createdAt": "2025-08-19 13:03:36.732586-06:00"
        }
    }
}

As you can see, the response is mostly the same as a money out transaction. But, after around 90 seconds (average time for most banks) the CEP Webhook will return the information parsed in the response. You could also manually fetch the transaction data, together with the updated metadata through the transactions endpoint.

GET /v1/clients/:client_id/transactions/:id

CEP Webhook Response

{
  "client_id": "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx",
  "payload": {
    "id_msg": "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx",
    "msg_name": "CEP",
    "msg_date": "2025-08-15",
    "body": {
      "id": "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx",
      "tracking_key": "20250815XXXXXX123456789",
      "beneficiary_account": "000000000000000000",
      "beneficiary_name": "Daniela Paola Santelices Chavez",
      "beneficiary_rfc": "XXXX000000XXX",
      "status": "COMPLETED",
      "processed_at": "2025-08-15 16:42:39.327313-06:00"
    }
  },
  "webhook_type": "CEP"
}

Transaction response

{
    "id": "UUID_1",
    "bankId": "UUID_2",
    "clientId": "UUID_3",
    "externalReference": "REF_001",
    "trackingId": "TRACKING_ID_001",
    "description": "Validacion de cuenta Finco",
    "amount": "0.01",
    "currency": "MXN",
    "category": "DEBIT_TRANS",
    "subCategory": "SPEI_DEBIT",
    "transactionStatus": "LIQUIDATED",
    "audit": {
        "createdAt": "2025-01-01 00:00:00.000000-00:00",
        "updatedAt": "2025-01-01 00:00:00.000000-00:00",
        "deletedAt": "None",
        "blockedAt": "None"
    },
    "jsonReference": "",
    "sourceInstrument": {
        "id": "UUID_4",
        "bankId": "UUID_2",
        "clientId": "UUID_3",
        "ownerId": "UUID_5",
        "instrumentAlias": "InternalAccount",
        "instrumentStatus": "ACTIVE",
        "instrumentType": "SENDER_RECEIVER",
        "instrumentDetail": {
            "accountNumber": "ACCOUNT_001",
            "clabeNumber": "CLABE_001",
            "holderName": "ANCV"
        },
        "rfc": "ND"
    },
    "destinationInstrument": {
        "id": "UUID_6",
        "bankId": "UUID_7",
        "clientId": "UUID_3",
        "ownerId": "UUID_3",
        "instrumentAlias": "CLABE",
        "instrumentStatus": "ACTIVE",
        "instrumentType": "SENDER_RECEIVER",
        "instrumentDetail": {
            "accountNumber": "ACCOUNT_002",
            "clabeNumber": "CLABE_002",
            "holderName": "BENEFICIARY_NAME"
        },
        "rfc": "RFC_001"
    },
    "metadata": {
        "dataCep": {
            "cepUrl": "https://example.com/cep/SPECIAL_URL_FOR_CEP",
            "validationId": "UUID_8",
            "beneficiaryName": "BENEFICIARY_NAME",
            "beneficiaryRfc": "RFC_001",
            "status": "COMPLETED",
            "createdAt": "2025-01-01 00:00:00.000000-00:00",
            "processedAt": "2025-01-01 00:00:00.000000-00:00"
        }
    }
}

Delivery & Retry Policy (CEP Webhook)

Total attempts: 17 (≈ 3:03 hrs total)
Phases:

Attempts 1–3: every 90s → t0, +1:30, +3:00
Attempts 4–6: every 5 min → +8:00, +13:00, +18:00
Attempts 7–17: every 15 min → from +33:00 … up to +3:03:00 (final attempt)

Detailed schedule (with webhook status)

Attempt	Delay from previous	Elapsed time	Webhook status (typical)
1	0:00:00	0:00:00	`PENDING_CEP`
2	0:01:30	0:01:30	`PENDING_CEP`
3	0:01:30	0:03:00	`PENDING_CEP`
4	0:05:00	0:08:00	`DELAYED`
5	0:05:00	0:13:00	`DELAYED`
6	0:05:00	0:18:00	`DELAYED`
7	0:15:00	0:33:00	`DELAYED`
8	0:15:00	0:48:00	`DELAYED`
9	0:15:00	1:03:00	`DELAYED`
10	0:15:00	1:18:00	`DELAYED`
11	0:15:00	1:33:00	`DELAYED`
12	0:15:00	1:48:00	`DELAYED`
13	0:15:00	2:03:00	`DELAYED`
14	0:15:00	2:18:00	`DELAYED`
15	0:15:00	2:33:00	`DELAYED`
16	0:15:00	2:48:00	`DELAYED`
17	0:15:00	3:03:00	`FAILED` (only if no CEP confirmation)

Webhook-reported states

PENDING_CEP → from t0 through attempt 3
DELAYED → from attempt 4 through attempt 16
FAILED → only if no confirmation by attempt 17

When the CEP is issued, the webhook will send COMPLETED (see “CEP Webhook Response” example below).

Example payload with intermediate states

{
  "client_id": "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx",
  "payload": {
    "id_msg": "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx",
    "msg_name": "CEP",
    "msg_date": "2025-08-15",
    "body": {
      "id": "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx",
      "tracking_key": "20250815XXXXXX123456789",
      "beneficiary_account": "000000000000000000",
      "beneficiary_name": "Daniela Chavez Juarez",
      "beneficiary_rfc": "XXXX000000XXX",
      "status": "DELAYED", // possible: PENDING_CEP | DELAYED | COMPLETED | FAILED
      "processed_at": null
    }
  },
  "webhook_type": "CEP"
}

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