Cashflow

Overview

Cashflow is an offline personal finance app for Android: transactions, budgets, bills, savings goals, and accounts, with a dashboard that pulls them together. I designed and built it for a fintech startup in Bolivia, in English and Spanish, with no backend; everything lives on the phone. It shipped, people used it, and the startup later took it off the store and now hands it out as a direct APK.

Problem

Most budgeting apps either show a wall of charts or nag. People open a money app for a quick answer, am I okay this month, and leave if the answer takes three screens or comes with a scolding. It also had to work offline, in two languages, and with a screen reader.

Process

1. 01I built the function first: transactions, budgets, bills, goals, the dashboard, settings, and onboarding were working with seeded data in the first two days, before any visual design. The design pass then had real edge cases to solve instead of a happy-path mockup.
2. 02I wrote the design direction down before styling anything. My first written direction was calm and grounded: pine green and clay, Fraunces and Hanken Grotesk, and a flow band on the dashboard comparing income with spending. Two hours later, before building any of it, I replaced the whole direction with a friendlier one. I wanted the hero to answer whether the month was going to plan, not only show the gap.
3. 03The dashboard became a month ring: the net in the middle, the ring filled by how much of the planned spending is used, and one plain status line under it, 'On track · $643 left'. The ring turns amber at 75% and coral at 90%. It's the only bold element on the screen.
4. 04My first color tokens failed contrast on white: income green at 2.55:1, spending coral at 2.89:1, goal honey at 1.95:1. I darkened all three and added separate darker text shades, so amounts read at 5.2:1 or better.
5. 05I built it for TalkBack: no meaning carried by color alone (a budget near its limit gets a 'Heads up' label and an icon, not just an amber bar), amounts read out with the currency name, privacy mode hides amounts from the screen reader too, and charts have a text version. An automated axe audit of 11 screens and sheets found 14 violations; I fixed all of them, and the final pass had none.
6. 06After the first tester build, I changed two flows. Marking a bill paid now creates the matching expense, and undoing it removes it, so bills and the ledger can't disagree. Installment purchases now always open to edit first, after the installment badge kept sending taps to the wrong panel.

Reflection

I chose offline with no backend so a person's money data never leaves their phone, and that choice left the biggest gap in the product: there's no backup. A lost or reset phone takes the whole history with it, and I never designed the export or restore flow that would fix that. It's also the first thing a careful user asks about a money app, and I'd design it before adding any new feature.