# Commercial Card Payment Initiation
source: https://developer.mastercard.com/payment-initiation-api/documentation/use-cases/commercial-card-payment-initiation/index.md

In this use case, the Debtor Agent initiates a new commercial card payment by submitting a payment initiation request to the Commercial Direct Payments (CDP) service.
Diagram step-1-mermaid

1. The Debtor Agent initiates a card payment request.
   API Reference: `POST /debtor-agents/{ica}/payment-initiations`

2. CDP validates the request.
3. CDP generates the `instructionIdentification`.
4. CDP returns a 201 Created response containing the `instructionIdentification` with a status of RECEIVED.

## Idempotency Support in Pyament Initiation {#idempotency-support-in-pyament-initiation}

The Commercial Card Payment Initiation API supports an optional `Idempotency-Key` header. By providing a unique client-generated UUID with a payment request, clients can safely retry requests without creating duplicate payments.

#### Benefits {#benefits}

* Prevents duplicate payment creation when the same request is submitted multiple times.
* Enables safe retry behavior during network failures, timeouts, or uncertain response conditions.
* Improves reliability and consistency of payment processing.

#### Request Behavior {#request-behavior}

|                                Scenario                                 |             Response              |
|-------------------------------------------------------------------------|-----------------------------------|
| New payment request (with or without an `Idempotency-Key`)              | `201 Created`                     |
| Duplicate request with the same `Idempotency-Key` and identical payload | `200 OK` with the cached response |
| Request with the same `Idempotency-Key` but a different payload         | `422 Unprocessable Entity`        |

#### Idempotency Key Validity {#idempotency-key-validity}

An `Idempotency-Key` remains valid for **24 hours**. After this period expires, the same UUID can be reused, and the system treats the request as a new payment event.