When building Depane, the goal was to create a seamless, globally accessible API for mobile airtime top-ups. The existing landscape for international airtime transfers is notoriously fragmented, so I wanted to build a centralized backend that could abstract away the complexities of dealing with hundreds of global telecom operators. I architected the platform as a robust API service using TypeScript, Express, and MongoDB, heavily utilizing a layered design to keep the codebase clean and maintainable.

The core of the application revolves around the Reloadly API integration, which I wrapped in a dedicated service layer to handle token caching, operator discovery, and fulfillment. To manage payments securely, I implemented a full Stripe integration with asynchronous webhooks. This was one of the most technically challenging parts of the build — ensuring that our local database states remained perfectly synchronized with both Stripe's payment status and Reloadly's fulfillment status, even under heavy load or intermittent network failures.

To ensure the API remained fast and responsive, I offloaded heavy processing tasks to background queues using Agenda. The result is a highly scalable, secure SaaS backend with robust role-based access control, currently supporting the live platform. Building this reinforced my deep understanding of asynchronous system design, third-party API orchestration, and resilient webhook handling.