Can AI get the interest calculations right?

Amortisation is a well-defined formula, so generated code is usually correct — but verify it. Enter one debt with round numbers, compute the first three months by hand, and compare. Money maths is the one place where "looks right" is not good enough.

Do I need to connect to real bank accounts?

No, and for a first version you should not. Bank aggregation (Plaid and equivalents) adds cost, compliance obligations, and a permissions screen that scares users off. Manual entry ships this week; add a bank connection only once people are paying.

How to Build a Debt Payoff App with AI (2026)

What a debt payoff planner app needs

Add debts with balance, APR, and minimum payment
Snowball (smallest balance first) vs avalanche (highest APR first)
Projected debt-free date and total interest saved
Log payments and watch the plan recalculate
Payoff progress chart across all debts

The screens

Screen	What it does
Overview	Total debt, debt-free date, progress ring
Debts	List of debts in payoff order with next-payment amounts
Add Debt	Name, type, balance, APR, minimum payment, due day
Strategy	Snowball vs avalanche side by side with the date and interest difference
Payment History	Logged payments and the balance curve over time

The data model

Debt: name, type, balance, apr, minimumPayment, dueDay
Payment: debtId, date, amount, principal, interest
Plan: strategy, extraMonthly, projectedFreeDate
User: email, subscriptionTier

The build prompt (copy this)

Paste this into ShipNative and it becomes a working React Native app with these screens, navigable in a live preview, in about two minutes:

“A debt payoff planner. Users add debts with balance, APR, and minimum payment, then choose snowball or avalanche. The app computes a month-by-month amortisation schedule, shows the projected debt-free date and total interest for each strategy, and recalculates when a payment is logged. Screens: Overview (total debt, debt-free date, progress ring), Debts (ordered by the chosen strategy), Add Debt, Strategy comparison, Payment History with a balance chart. Works offline. Include an "extra monthly payment" slider that updates the projected date live.”

Then iterate with small, screen-specific prompts (“make the primary button bigger”, “add an empty state”), preview on your own phone, and export the full Expo project whenever you want. The full method: how to build an app with AI.

How it makes money

Subscription ($3–5/mo) gated at the third debt and on the strategy comparison. Be careful with framing: people using this app are, by definition, short on money. A one-time unlock ($15–25) often converts better here than a recurring charge, and it is the more honest offer.

Implementation and the revenue math for every model: how to make money from an app. When you’re ready to ship: App Store and Google Play publishing guides.

Build it now

The prompt above is free to run at shipnative.dev — working debt payoff planner app on your phone today, full code export, no credit card.

How to Build a Debt Payoff App with AI