A customer in Malawi approached us with a request to extend their mobile application, which is used for purchasing crops from farmers, by adding the ability to issue electronic payment vouchers. The goal was to leverage the existing API from Unayo Bank, which enables the creation of one-time vouchers that recipients can redeem in cash directly from an ATM — without the need for a payment card. The challenge was to ensure the generation of secure, unique voucher codes and to build a robust system for communicating with the banking API, even in environments with limited internet connectivity.
We developed a complete API integration into the existing FileMaker database. The process starts in the mobile app used by employees during the crop purchasing process. Here, a unique voucher number is generated, matching the format of the allocated number range.
This number, along with transaction details, is sent to the server side. The server first registers the voucher internally and then attempts to register it via an HTTP request to the API. If the request is successful, it receives a confirmation, and the voucher becomes available for cash withdrawal at an ATM. If the connection is unavailable, the system automatically retries the registration until a connection is established.
The entire solution includes a notification mechanism for management in case voucher registration fails even after multiple attempts. At the same time, everything is designed to allow the mobile app to operate offline and send data later, once the connection is restored.
