Overview

This example illustrates a complete end-to-end flow for a two-step payment using Credit Card, where the transaction is split into:

• Authorization (AUTH) → funds are reserved
• Capture (CAPTURE) → funds are collected

It demonstrates how the merchant system:

• Creates a checkout configured for authorization
• Processes customer interaction through the hosted payment form
• Receives asynchronous updates via Webhooks
• Confirms the authorization result using the Status Inquiry endpoint
• Executes a separate capture operation
• Validates the final captured state

This scenario represents a multi-phase transaction flow, requiring strict control of transaction state transitions and correct orchestration between authorization and capture steps.

The execution of this flow can be validated using the SIBS Postman Collections:

• Download SIBS PAYMENT GATEWAY POSTMAN Collection
• Download SPG Sandbox POSTMAN Collection

Goal

Authorize a payment using a credit card and capture the funds in a separate step, ensuring:

• Correct authorization handling
• Proper separation between authorization and capture
• Reliable state validation before capture
• Final reconciliation after capture

Preconditions

Before executing this flow, the following must be in place:

• Valid SPG credentials:
  • terminalId
  • X-IBM-Client-Id
  • Bearer token
• Configured Webhook endpoint
• Backend capable of storing:
  • transactionID
  • merchantTransactionId
• Hosted form integration correctly implemented

In Postman, ensure the following variables are configured:

• terminalId
• ClientID
• Bearer
• host

(See collection root variables in SIBS PAYMENT GATEWAY POSTMAN Collection)

Step 1 – Create Checkout

The merchant creates a checkout configured for authorization.

Endpoint

POST <ROOT_URL>/api/v2/payments

Headers

Authorization: Bearer <AuthToken>
X-IBM-Client-Id: <clientId>
Content-Type: application/json
Accept: application/json

Example Request

{
    "merchant": {
        "terminalId": 11111,
        "channel": "web",
        "merchantTransactionId": "ORDER-AUTH-0001"
    },
    "transaction": {
        "transactionTimestamp": "2026-04-15T11:00:00.000Z",
        "description": "Authorization payment",
        "paymentType": "AUTH",
        "amount": {
            "value": 100.00,
            "currency": "EUR"
        },
        "paymentMethod": [
            "CARD"
        ]
    }
}

Execute this step in Postman using:

Collection Path:

SIBS PAYMENT GATEWAY → Card → Checkout Card

Key Outputs

• transactionID → primary identifier
• formContext → required for hosted form

The transactionID returned in this step must be used as the primary identifier across all subsequent steps, including webhook processing and status validation.

Step 2 – Customer Interaction (Authorization)

The customer is redirected to the hosted payment form.

<script src="https://spg.qly.site1.sibs.pt/assets/js/widget.js?id={transactionID}"></script>

<form
  spg-context="{formContext}"
  spg-config='{"redirectUrl":"https://merchant.example.com/return"}'>
</form>

At this stage:

• The customer enters card details
• 3DS authentication may occur
• SPG processes the authorization request

Step 3 – Handle Customer Redirection

After authorization, the customer is redirected to the merchant.

Important

 

The redirect does not guarantee that the authorization is finalized.

 

At this point, the transaction may still be:

• Pending
• InProcessing
• Success

Recommended behavior:

• Display a “processing authorization” state
• Trigger backend validation

The backend must use the transactionID obtained during checkout to perform a Status Inquiry request.

Step 4 – Receive and Process Webhook Notifications (Authorization)

SPG sends a notification with the authorization result.

Example Payload

{
    "returnStatus": {
        "statusCode": "000",
        "statusMsg": "Success"
    },
    "paymentStatus": "Success",
    "paymentMethod": "CARD",
    "transactionID": "s2ExampleTxAUTH123",
    "paymentType": "AUTH",
    "notificationID": "notif-auth-001"
}

Processing Requirements

• Receive the notification
• Validate authenticity and integrity according to the configured webhook security model (e.g., decryption and header validation)
• Store and process the notification using notificationID as a unique identifier
• Ensure idempotent processing
• Acknowledge correctly

Response to SPG

{
    "statusCode": "000",
    "statusMsg": "Success",
    "notificationID": "notif-auth-001"
}

The notificationID must match the value received in the webhook payload.

Important

 

Webhooks provide event-driven updates only.

 

They must not be used to determine the final transaction outcome.

Step 5 – Confirm Authorization (Status Inquiry)

The merchant must confirm that authorization was successful.

Endpoint

GET <ROOT_URL>/api/v2/payments/{transactionID}/status

Headers

Authorization: Bearer <AuthToken>
X-IBM-Client-Id: <clientId>
Content-Type: application/json
Accept: application/json

Execute this step in Postman using:

Collection Path:

SIBS PAYMENT GATEWAY → Card → getStatus

Example Response

{
    "returnStatus": {
        "statusCode": "000",
        "statusMsg": "Success"
    },
    "paymentStatus": "Success",
    "paymentType": "AUTH",
    "transactionID": "s2ExampleTxAUTH123",
    "amount": {
        "value": 100.00,
        "currency": "EUR"
    }
}

Capture must only be performed if the authorization is confirmed as successful.

 

This ensures consistency between event execution, webhook notifications, and backend processing, particularly in scenarios involving delays, retries, or asynchronous flows.

Step 6 – Capture the Payment

The merchant must confirm that the capture operation has been successfully completed.

Endpoint

POST <ROOT_URL>/api/v2/payments/{transactionID}/capture

Headers

Authorization: Bearer <AuthToken>
X-IBM-Client-Id: <clientId>
Content-Type: application/json
Accept: application/json

Execute this step in Postman using:

Collection Path:

SIBS PAYMENT GATEWAY → Card → Capture

Example Request

{
    "amount": {
        "value": 100.00,
        "currency": "EUR"
    }
}

Step 7 – Receive Webhook (Capture)

SPG sends a notification for the capture operation.

Example Payload

{
    "returnStatus": {
        "statusCode": "000",
        "statusMsg": "Success"
    },
    "paymentStatus": "Success",
    "paymentType": "CAPTURE",
    "transactionID": "s2ExampleTxAUTH123",
    "notificationID": "notif-capture-001"
}

Process this webhook using the same idempotent model.

Step 8 – Confirm Final State (Status Inquiry)

The merchant must confirm that the capture operation has been successfully completed.

Endpoint

GET <ROOT_URL>/api/v2/payments/{transactionID}/status

Headers

Authorization: Bearer <AuthToken>
X-IBM-Client-Id: <clientId>
Content-Type: application/json
Accept: application/json

Example Response

{
    "returnStatus": {
        "statusCode": "000",
        "statusMsg": "Success"
    },
    "paymentStatus": "Success",
    "paymentType": "CAPTURE",
    "transactionID": "s2ExampleTxAUTH123"
}

Authoritative Rule

The Status endpoint is the single source of truth for the final transaction state.

This ensures consistency between:

• Customer interaction (frontend)
• Webhook notifications
• Backend processing

This ensures consistency between event execution, webhook notifications, and backend processing, particularly in scenarios involving delays, retries, or asynchronous flows.

Expected Final Outcome

• Authorization → Success
• Capture → Success

Only after capture success should the merchant consider the payment completed.

Implementation Notes

• Authorization and capture are independent steps
• Capture must never be executed without confirmed authorization
• Webhooks must be processed idempotently
• Status must always be used for final validation
• Partial captures may be supported depending on configuration
• Time limits for capture may apply

Use of Postman Collection

The Postman Collections should be used as the execution layer for this example.

Relevant Requests

• Checkout

SIBS PAYMENT GATEWAY → Card → Checkout Card

• Status

SIBS PAYMENT GATEWAY → Card → getStatus

• Capture

SIBS PAYMENT GATEWAY → Card → Capture

Use the previously referenced requests to execute each step, validate responses, and simulate different transaction outcomes in sandbox environments.

Recommended Usage

• Execute authorization flow
• Validate status before capture
• Execute capture
• Validate final status

Final Notes

This example demonstrates a complete two-step payment flow requiring strict control of transaction state.

For production-grade implementations:

• Use API responses for immediate control
• Use Webhooks for event awareness
• Use Status Inquiry for final validation

This ensures correct handling of multi-phase payments and avoids inconsistent or premature transaction finalization.