Understanding how financial service design works means following that method, from the first user interview to the metrics that prove a redesign paid off. It is a discipline that increasingly decides outcomes in a US fintech market worth about $66.82 billion in 2026 and forecast to reach roughly $135.42 billion by 2031, according to Mordor Intelligence’s US fintech market report. This guide walks through the stages a financial service passes through as it is designed, who is involved, and how teams know whether the design actually worked. The stages at a glanceThe table below summarizes the typical stages of designing a financial service and the question each one answers. Completion and retention dataSources: Mordor Intelligence US fintech market report; Fortune Business Insights fintech market report, which projects the global fintech market to grow from $394.88 billion in 2025 to $1.13 trillion by 2032.