This document outlines the major challenges of developing a fintech mobile app. It discusses 5 key challenges: 1) Planning the idea and determining technical feasibility and user benefits. 2) Finalizing the appropriate technology stack. 3) Identifying the app complexity based on desired features. 4) Defining the right user experience design. 5) Ensuring data privacy and security standards are met. For each challenge, it provides questions that should be asked to properly address that challenge during the app development process.