We designed the end-to-end mobile experience for EXPay, a digital wallet application providing payments, balance management, charging, gifting, and transaction history features. The project focused on structuring complex financial flows into clear, task-oriented user journeys — including wallet charging, gift transfers, password verification, and purchase confirmations. A mobile-first UI system was designed to ensure consistency, accessibility, and clarity across high-frequency payment scenarios. Special attention was given to reducing cognitive load in sensitive moments such as authentication, payment completion, and error states, while maintaining a clean and trustworthy visual language appropriate for a fintech product.