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Webhooks Validation

Validation request is sent for Cashier and Virtual Terminal - immediately after the payment details have been submitted by the customer within the Cashier, or by the agent using the Virtual Terminal, and before the actual transaction processing. The validation call lets you apply the logic on the CRM side in order to confirm or reject this submission before the processing has been attempted.

{danger.fa-exclamation} IMPORTANT #1: The validation callback will be triggered only if the validation_url is provided within the Cashier session request.

{danger.fa-exclamation} IMPORTANT #2: In case if your API response contains "status":0, the validation is considered to be successfully passed, and the payment will be attempted.

Response containing any other status value is treated as failed validation, message in "description" parameter of the response will be shown to customer as reason for the blocked attempt.

Response timeout or malformed response (integer status or string description missing or having the wrong data type, response that appears to be not a JSON string, or a JSON that does not contain an object) is considered as an error, and the validation will be failed with a generic error.


✓ - required value
? - optional, value or null
✕ - always appears as null

Variable Type Description
merchant_id varchar(50) Merchant API client account identifier
application_key varchar(32) Identifier of your application (website)
customer <Object> Customer object
session <Object> Session object
transaction_attempt <Object> Transaction attempt object
version varchar(3) API version
timestamp int(11) Request time (unix timestamp, seconds)


Variable Type Description
status int API communication status - for transaction processing status please refer to transaction.transaction.status
- 0 if the request was successful
- Negative integer if internal server/network error occurs
- Positive integer if application/logical error occurs
description varchar(256) Accurate description of the result. Return the actual error for any exception as it helps to diagnose issues in production
version varchar(3) API version
timestamp int(11) Response time (unix timestamp, seconds)


The full signature generation algorithm can be found in the Authentication section.

Request signature parameters

  1. merchant_id
  2. application_key
  3. timestamp
  4. customer.customer_token
  5. session.order_id
  6. transaction_attempt.currency
  7. transaction_attempt.amount
  8. transaction_attempt.conversion_rate
  9. transaction_attempt.attempted_currency
  10. transaction_attempt.attempted_amount

Response signature parameters

  1. status
  2. timestamp


Incoming Request

    "merchant_id": "Test-Integration-Merchant",
    "application_key": "Sandbox",
    "customer": {
        "customer_token": "87cfb23a8f1e68e162c276b754d9c061",
        "country": "GB",
        "first_name": "John",
        "last_name": "Johnson",
        "avs_alert": 0,
        "verification_alert": null
    "session": {
        "auth_token": "8a7sd87a8sd778ac961062c6bedddb8",
        "intent": "payment",
        "session_status": "created",
        "order_id": "test-1560610955",
        "currency": "EUR",
        "amount": 100,
        "conversion_rate": 1.000000,
        "processed_currency": "EUR",
        "processed_amount": 100,
        "payment_method": "Credit Card",
        "gateway": null,
        "pin": "1",
        "variable1": "your variable",
        "variable2": "if that is not enough, you can pass even one more variable",
        "variable3": null
    "transaction_attempt": {
        "intent": "sale",
        "currency": "EUR",
        "amount": 100,
        "conversion_rate": 1.000000,
        "attempted_currency": "EUR",
        "attempted_amount": 100,
        "payment_method": "Credit Card",
        "card_data": {
            "card_number": "411111******1111",
            "card_exp": "12\/2024",
            "cvv": "***"
        "wallet_data": null,
        "withdrawal_request_id": null
    "version": "1.3",
    "timestamp": 1590611635

Response (Success)

    "status": 0,
    "description": "Ok",
    "version": "1.3",
    "timestamp": 1590611635

Response (Error)

    "status": 1,
    "description": "Transaction already updated manually at the website to final status",
    "version": "1.3",
    "timestamp": 1590611635