Cash Runway

Cash Runway helps small business owners forecast 90 days ahead, detect cash shortfalls early, and test payment delays before they become a crisis.

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Inspiration

Small business owners often know their sales, but they do not always know whether the cash in their bank account will be enough several weeks from now.

A business can appear profitable and still face a cash shortage because payroll, rent, subscriptions, taxes, and supplier payments arrive before expected income. Traditional accounting tools record what has already happened, but many owners need a simpler answer to a more immediate question:

Will I have enough cash to keep operating over the next 90 days?

I built Cash Runway to make that answer visible without requiring accounting knowledge, complex setup, or bank account integration.

What it does

Cash Runway is a lightweight cash-flow forecasting app for freelancers and small business owners.

Users enter their current cash balance, expected income, payments, and recurring fixed costs. The app then calculates a forward-looking cash forecast and helps users:

  • View projected balances 30, 60, and 90 days ahead
  • Identify the lowest projected balance and the date it occurs
  • Detect possible cash shortfalls before they become urgent
  • Register and manage expected income and expenses through a calendar
  • Add recurring costs such as payroll, rent, and subscriptions
  • Simulate delayed customer payments
  • Compare how delays affect the full 90-day cash runway
  • Use the app in Japanese, English, Spanish, French, or German

Cash Runway is intentionally not a full accounting system. It focuses on one job: helping small business owners see future cash pressure quickly and make decisions early.

How I built it

Cash Runway was built as an iOS mobile application using React Native, Expo, and TypeScript.

The forecasting engine converts expected income, expenses, and recurring costs into a daily cash-flow timeline. From that timeline, the app calculates future balances, the lowest balance point, and potential shortfall dates.

The interface was designed around three principles:

  1. Simple input
  2. Instant understanding
  3. Lightweight operation

RevenueCat manages the monthly and annual Pro subscriptions, product offerings, purchases, entitlement status, and restoration of previous purchases. Pro access unlocks expanded recurring-cost capacity and extended payment-delay simulations.

RevenueCat integration

RevenueCat is the foundation of Cash Runway's subscription system.

The app uses RevenueCat to:

  • Retrieve subscription offerings
  • Display monthly and annual Pro plans
  • Process in-app subscription purchases
  • Check the user's active entitlement
  • Unlock Pro features
  • Restore previous purchases

This separates subscription management from the forecasting logic and provides a more reliable purchase experience for users.

Challenges I ran into

One major challenge was keeping date-based cash-flow calculations accurate across calendar navigation, local time zones, recurring costs, and payment-delay simulations.

Another challenge was simplifying the interface. Cash-flow forecasting can easily become as complicated as accounting software, so I repeatedly removed unnecessary screens and controls. Normal income and expenses are managed through the calendar, while fixed costs remain clearly identified.

App Store review and subscription configuration were also important challenges. I worked through product setup, RevenueCat offerings, purchase restoration, privacy information, and subscription disclosure requirements.

Accomplishments that I am proud of

I am proud that Cash Runway turns multiple future transactions into one clear operational signal: the amount of cash a business is expected to have and the date when its balance may be at its lowest.

I also completed the product as a solo developer, including the application design, forecasting logic, localization, subscription integration, testing, legal pages, App Store preparation, and demonstration video.

What I learned

I learned that financial tools do not always need more features. For small business owners, clarity and early warning can be more valuable than a large accounting dashboard.

I also learned how important it is to design subscription access as part of the product architecture rather than adding it at the end. RevenueCat made it possible to keep entitlement handling consistent while I focused on the user experience and forecasting logic.

What's next for Cash Runway

The next steps are to improve the daily, weekly, and monthly forecast views and add clearer visual comparisons between the normal forecast and delayed-payment scenarios.

I am also considering export tools for sharing a 90-day forecast with accountants, financial advisers, and business partners while keeping the app lightweight.

Award category

Cash Runway is submitted for the RevenueCat Peace Prize because its purpose is to reduce financial uncertainty and help small business owners identify cash-flow problems before they become crises.

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