In Sandbox, it's possible to simulate Card Transactions for testing purposes.

Authorization

An authorization may be simulated by sending a POST request to the Transactions endpoint. The amount is the purchase amount, not negated as it is in the Transaction Object. The merchant_name comes back in the Transaction Object as description.

Settlement

A settlement may be simulated by sending a PUT request to the Transactions endpoint, using the transaction_id returned from the POST request above. The settlement amount may be different from the authorization amount, e.g., if a cardholder spends $100 at a restaurant and tips $20, the authorization is for $100 and the settlement is for $120.