Design a feature for a banking app that helps users save more money.

Model answerI'd focus on behavioral economics — making saving automatic and rewarding. Users don't save because the friction of deciding when and how much is too high. My solution: 'Roundup Savings' — every purchase rounds up to the nearest unit, the difference goes to savings. Simple, automatic, visible. I'd track adoption rate, weekly savings amount, and whether users feel in control of their money.