Overview
A forward-looking financial forecasting tool designed to eliminate cash flow guesswork. By mapping future income, recurring bills, and variable credit card due dates directly onto an interactive calendar, the app transforms abstract bank balances into a clear, day-by-day financial timeline.
Role: Creator, Product Designer, Developer
Tools used: Figma, Claude Code
Download on the App Store
Why I Built It
I built Otally to solve my own problem. I was tracking my finances in an Excel spreadsheet so I could see how much money I'd have in my account and how much I could save. As the months added up, it got messy, and copying formulas into every new month became tedious. Before designing, I tried existing forecasting apps, including Cashflows Pro, Balance Forecasting and ForeCash. None gave me exactly what I wanted: a clear, day-by-day view of my future balance in an app that was simple, affordable, and private.
Problem
Banking apps show today’s balance or what you’ve already spent. They don’t answer the question that matters most: will I have enough in my account when my bills and credit card payments come due? Without one timeline for paydays, bills and card due dates, it’s easy to overdraft or miss a payment.
Goal: Help people spot low-balance days before they happen and plan payments with confidence, using forecasting instead of after-the-fact budgeting.
Key Features
1. Forward-looking balance timeline
Instead of focusing on past spending categories, Otally projects your daily balance from scheduled income, recurring subscriptions and upcoming bills.
Calendar and list views: See your balance on a calendar, or switch to a list of only the days with transactions.
Why: I wanted to see my balance and spending each day, so a calendar was the clearest way to show it. The tradeoff is that a calendar gets small on a phone screen, which makes details hard to read. To solve that, I added a list view that shows only the days with transactions.
2. "What-if" scenario engine
Simulate a purchase before you make it.
Real-time simulation: Enter a cost and a date to see how it affects your balance months ahead.
Decision clarity: Know whether you can afford a big purchase before you make it.
Why: I left out budget categories because knowing how much I'd spent on groceries didn't answer my real question: how much will be in my account later? The what-if engine lets people forecast an expense and immediately see how it changes their future balance.
3. Recurring bills and low-balance days
Recurring engine: Simple setup for bi-weekly paychecks, monthly rent, and annual subscriptions.
Low-balance days: Days when your balance falls below your low-balance amount are highlighted on the calendar and listed below it.
Why: Because Otally is a forecast, people see a low balance as soon as they enter a transaction; nothing happens behind the scenes. Each person sets their own low-balance amount, the number they never want their account to drop below, which works as a personal buffer.
4. Private and affordable
No account needed: Your data stays on your device.
Why: I kept Otally private by design. Everything is stored only on the user’s device, with no database behind it, so people don’t need an account or even an email to start. It costs $1.99 a month or $49.99 for lifetime access, much less than other forecasting apps.
Designing and Building
Building Otally myself let me use it the way a real person would, and that changed the design. The date detail view looked good and tested well in Figma, but once I started coding, I realized it needed more functionality. Deleting an entry took effect immediately, before the user saved, so I changed it to happen only on save. I also added a way to create a transaction from that same view, so people can stay on the day they're looking at. Handing my Figma designs to Claude Code to build taught me that a good handoff spells out the in-between steps, not just the final screens.
Component Library
I documented Otally's interface as a component library, the same way I approach design systems at work. It brings colors, typography, buttons, inputs, navigation, calendar and list items together in one place.
App Gallery
What's Next
Otally is live on the App Store. So far, I’ve tested it informally with friends and family. My next step is getting it in front of more people, running more structured user tests, and refining the app based on what I learn.
Download on the App Store