The problem
Brex wanted to launch a mobile banking app to complement their web platform, but their mobile team was fully allocated to the existing card product. They needed an external team that could take the project from concept to App Store in under four months.
Our approach
We ran a two-week discovery sprint to define the core feature set, then moved into parallel design and development tracks. The app was built natively — Swift for iOS and Kotlin for Android — with a shared API layer. We shipped weekly builds to TestFlight and internal testers, iterating on feedback continuously.
Results
The app launched on schedule with a 4.8-star rating in its first month. Key features included instant card controls, real-time transaction notifications, and receipt capture. The native approach paid off in performance — cold start was under 800ms on both platforms.