Marnie

Marnie app icon — 1024 × 1024, uncropped
Dashbaord
Transaction History
Planning, creatign budgets, settings Goals
Insights
AI Chat, Voice to Transactions
Manual Expense and Income input
Android Automatic transactionnotification Capture
Apply Pay auto capture

Inspiration

Money tracking often asks people to do the most work when they have the least time. Marnie brings capture, transaction review, planning and spending context into one friendly mobile companion. The goal is to make everyday money habits easier to maintain.

What it does

Record income and expenses, organize accounts, review transaction history, set category spending limits, track upcoming bills and savings goals, and explore spending insights. A helpful owl coach makes the interface approachable. Receipt, voice and supported device capture workflows reduce manual entry while keeping transactions reviewable. Safe-to-spend and forecast screens explain the assumptions behind their estimates.

How I built it

Marnie uses React Native, Expo and TypeScript for iOS and Android. SQLite supports local data, with Supabase providing authentication and backend services. The architecture separates device workflows from optional cloud AI processing. Native integrations include Android notification capture and Apple Shortcuts workflows on supported devices.

RevenueCat powers weekly, monthly and annual Pro subscriptions and entitlement checks through its React Native SDK. Pro expands capture and planning capabilities, with bounded allowances for cloud AI features.

Challenges and lessons

The main challenge was keeping capture reliable without making financial records feel automatic or opaque. Different currencies, categories, recurring payments, account balances and incomplete inputs need clear review paths. Forecasts must distinguish assumptions from reconciled balances. I also worked through native permissions, local storage, subscription synchronization and the different requirements of both app stores.

What I am proud of

Marnie connects a small action, such as saving an expense, to useful context in transaction history, category budgets and insights. The owl coach, colorful category icons and consistent planning screens give a complex topic a more welcoming interface. The demo uses clearly labeled fictional transactions in a test account.

Availability and next steps

Marnie: Expense Tracker is live on Google Play. The iOS app has been submitted to Apple and is awaiting approval. Next steps are to learn from the first public users, refine capture and transaction review, and make planning guidance clearer as more real-world feedback arrives.