New Payment Simulation Capabilities in the Sandbox

The sandbox payment simulator has been enhanced with new functionality to help you test more realistic payment scenarios.

These updates make it easier to simulate complete payment lifecycles, including new payment schemes, FX conversions, and rerouting scenarios, without leaving the sandbox environment.

Simulate incoming FPS and SEPA payments

You can now simulate incoming Faster Payments Service (FPS), SEPA Credit Transfer and SEPA Instant payments using the POST /api/v1/payments/simulations/credits endpoint.

Previously, the simulator only supported simulating SEPA Direct Debit, and BACS Direct Debit. This update allows you to test more common scenarios.

To simulate these new payments, set the scheme value to either SEPA (SEPA Credit Transfer), SEPAINST (SEPA Instant) or FPS (Faster Payments Service) when making a request to the POST /api/v1/payments/simulations/credits endpoint.

FX

All incoming and outgoing payment simulations now support automatic currency conversion when the creditor or debtor account currency differs from the payment’s transfer currency.

For example: if you simulate an outgoing payment in EUR (e.g. a SEPA Direct Debit collection) from an account denominated in GBP, the simulator will automatically apply a conversion to reflect the currency difference.

The resulting payment will behave as if the FX conversion were processed by the bank, helping you test how your system handles FX rate data, converted amounts, and reporting flows.

To initiate an incoming payment involving FX, use an account denominated in a currency different from the amount.currency specified in your simulation request.

Note: remember that the amount.currency must also match the scheme currency.

The New Reroute Scenario

A new reroute test scenario has been added when simulating outgoing SEPA Instant payments. This test scenario will trigger a routing notification stating that the payment was rerouted from SEPA Instant to T2.

It allows you to test how your system handles payments that are automatically rerouted to another network (in this case T2) when SEPA Instant is unavailable or unsupported for a given counterparty. Read more about automatic rerouting.

Note: whilst the notification is triggered automatically when running this test scenario, you must ensure that you subscribe to that particular notification type. Read more about setting up webhooks.

This scenario can be triggered using the parameters listed below: