Designed a native mobile budgeting app for couples and roommates, solving the communication and visibility gap in shared financial management situations. Existing budgeting apps treat a household as a single account, one login, one view, one perspective. Dime was designed for the reality that shared finances involve two people with different behaviours and a constant need to communicate about money without it becoming conflict. The core design challenge was how two people see the same financial reality from their own perspective without duplicating data or splitting into two products. The identity-first home screen establishes whose session it is before any financial data appears. Both users see the same totals, but with states rendered from their individual perspective, one source of truth, two experiences. Messaging is tied directly to transactions rather than pushed to SMS, keeping communication and data together. Exception states like exceeded budgets were treated as primary interactions, not edge cases, and the budget edit flow was fully designed to demonstrate end-to-end ownership beyond the read state.