My parents are approaching retirement. They're not bad with money — they pay their debts, they save, they manage. But for years they've been caught in the same cycle: buy on credit, pay it off with their paycheck, lean on their year-end bonus for the bigger stuff. It works. Until retirement, when the bonus disappears.
Nobody has ever shown them clearly what that cycle is actually costing them. Or what would change if they broke it.
My aunt just got her first car loan. She wants to know: if she pays a little extra one month, does it actually matter? By how much?
And me — I'm just starting my career. I've watched people around me get trapped in debt patterns and I don't want that. But I also know at some point I'll need credit, and the idea of it getting out of hand scares me a little.
I couldn't find an app that answered these questions simply. Every finance app I tried was either too complex, too judgmental, or designed for people who already understood money. So I built one.
What is Zas?
Zas is a mobile-first financial awareness app for beginners. It doesn't track your spending. It doesn't judge your habits. It does one thing: it shows you the real impact of your financial decisions — in seconds.
We call them "Zas moments" — that spark of clarity when something that felt complicated suddenly makes sense:
"Zas. At this pace, you'll be paying this debt for 5 years and $3,200 of that is pure interest."
"Zas. Paying $100 more per month means you finish 2 years earlier and save $1,500."
"Zas. You won't reach your savings goal at this pace — but $50 more per month gets you there on time."
The app doesn't make decisions for you. It makes sure you understand yours.
How I built it with MeDo
I built Zas entirely through MeDo — an AI platform that lets you build full-stack applications through natural language conversations.
I had never thought of myself as someone who could build a complete app. But MeDo changed that.
The process worked in layers. I'd describe a feature in plain language — "I want a screen that shows the user how long it will take to pay off their debt, and compares what happens if they pay more" — and MeDo would generate the code, suggest the data structure, and help me think through edge cases I hadn't considered.
Some things I built through conversation with MeDo:
The amortization engine. Month-by-month debt payoff simulation, including a prior payments calculator that reconstructs how much of what you've already paid went to interest vs. principal. It handles edge cases like negative amortization (when your payment doesn't even cover the monthly interest) and very small remaining balances.
The Zas Moment screen. The core of the app. This single screen takes three inputs — balance, monthly payment, interest rate — runs the simulation, and delivers a clear insight plus a real-time comparison. The adjustment slider lets users drag to explore "what if I pay more?" without leaving the screen. The results update instantly.
The full stack. React frontend, Supabase for auth and database with Row Level Security on all tables, deployment through MeDo's marketplace. All of it generated and iterated through conversation.
The most important thing I learned: the quality of what you build with AI depends entirely on how clearly you can describe what you want. Not technical skill — clarity. The more specifically I could describe the experience I wanted a user to have, the better the result.
The hardest part
Getting the financial calculations right.
It's easy to build a simple debt calculator. But real-world debt is messier — people have been paying for months already, they've paid different amounts at different times, their remaining balance isn't what they think it is.
I had to go back and forth with MeDo many times to get the prior payments simulation right. We'd test edge cases: what if they've been paying for 3 years but at a low amount that didn't cover the interest? What if the balance has actually grown? The final version handles all of that — it shows users a breakdown of everything they've paid so far, how much went to interest (in red), how much reduced the principal (in green), and what's actually left.
That moment when a user sees "you've paid $4,200 so far but $2,800 of that was interest" — that's a Zas moment. That's the whole point.
What's next
Zas is live at https://app-b14zgyo7tmv5.appmedo.com.
I'm submitting it to the Build with MeDo Hackathon in the Learning & Education category.
If you try it, I'd genuinely love to know what you think — especially if you hit something confusing or something that didn't feel right. This is a real tool I'm building for real people, and early feedback shapes everything.
Drop a comment below or find me on dev.to. The more honest the better.
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