Penny Validation API
Copy for LLM
Copy page as Markdown for LLMs
View as Markdown
Open this page as Markdown
Open in ChatGPT
Get insights from ChatGPT
Open in Claude
Get insights from Claude

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)
Data delivery: CEP results are delivered via a dedicated CEP webhook for Penny Validation.
Transient initial state Immediately after creation, metadata.dataCep.status may briefly be INITIALIZED. Treat it as equivalent to PENDING for client logic/UI.
RFC is optional in the Instrument: You may register instruments with rfc = "ND"

CEP status values

Client-facing values for metadata.dataCep.status are:

INITIALIZED — transient initial state right after creation; typically flips to PENDING within seconds. Do not build distinct flows based on this state.
PENDING — waiting for CEP retrieval/confirmation.
DELAYED — CEP is taking longer than expected; background retries continue.
COMPLETED — CEP available and validated.
FAILED — CEP unavailable or permanently failed.

Note: Treat INITIALIZED the same as PENDING in client logic and UI.

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
  "description": "Validacion de cuenta",  // optional (max 40 chars)
  "external_reference": "1234567"             // optional (max 7 digits)
}

Field behavior & defaults

`description` (optional)

Type: string (letters numbers and spaces only; special characters not allowed, except ñ/Ñ)
Max length: 40 characters
If provided, it is stored as the transaction description/concept.
If not provided, backend sets:
- Default: "Validacion de cuenta"

It must be visible in:

GET /v1/clients/{clientId}/transactions/{transactionId} (description)
Penny Validation webhook/notification (concept field, e.g. payment_concept)

`external_reference` (optional)

Type: string (numeric)
Max length: 7 digits
If provided, it is stored as-is (no formatting changes).
If not provided, backend generates a default based on transaction_date:
- Default format: ddmmaa (e.g. 24/11/2025 → "241125")

It must be visible in:

GET /v1/clients/{clientId}/transactions/{transactionId} (external_reference / externalReference depending on API casing)
Penny Validation webhook/notification

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": "1234567",
    "trackingId": "20250820FINCHXXXXQ6RPX4",
    "description": "Validacion de cuenta",
    "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": "PENDING",
            "createdAt": "2025-08-19 13:03:36.732586-06:00"
        }
    }
}

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.

Note: Immediately after creation, the very first read may briefly return INITIALIZED before transitioning to PENDING. Clients should treat INITIALIZED as equivalent to PENDING for logic and UI.

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",
      "external_reference": "1234567",
      "payment_concept": "Validacion de cuenta para Colegiatura",
      "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"
}

Defaults in webhook: If description is omitted, payment_concept defaults to "Validacion de cuenta".
If external_reference is omitted, it defaults to the operation date formatted as ddmmaa (e.g. 24/11/2025 → "241125").

Transaction response

{
    "id": "UUID_1",
    "bankId": "UUID_2",
    "clientId": "UUID_3",
    "externalReference": "1234567",
    "trackingId": "TRACKING_ID_001",
    "description": "Validacion de cuenta",
    "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", // possible: INITIALIZED (transient) | PENDING | DELAYED | COMPLETED | FAILED
            "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`
2	0:01:30	0:01:30	`PENDING`
3	0:01:30	0:03:00	`PENDING`
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 → 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: INITIALIZED (transient) | PENDING | DELAYED | COMPLETED | FAILED
      "processed_at": null
    }
  },
  "webhook_type": "CEP"
}

Penny Validation APICopyCopy for LLMCopy page as Markdown for LLMsView as MarkdownOpen this page as MarkdownOpen in ChatGPTGet insights from ChatGPTOpen in ClaudeGet insights from Claude