How a Spreadsheet Became the PayOff Pro Mortgage App
TL;DR: Tracking my mortgage in a spreadsheet quietly rewired my behavior. The more progress I saw, the more extra payments I made. That tracking habit became PayOff Pro — a mortgage payoff tracker app — and eventually three more iOS apps. No coding background. Just clarity, AI, and a problem worth solving.
![A hand-drawn mortgage tracking spreadsheet transforming into a polished iPhone app screen][image-1] From a personal spreadsheet to an App Store listing — the path was shorter than I expected, and harder than I admitted.
Why I Started Tracking My Mortgage in a Spreadsheet
I did not set out to build four apps. I started with a spreadsheet.
My day job is in trade finance operations at a bank — commercial letters of credit, documentary collections, bank-to-bank reimbursements. I have spent my entire career in banking, and nothing about my background would ever suggest that I would develop iOS apps or ship anything on the App Store. But I do know what it feels like to watch a number move in the right direction, and that is where the story actually begins.
After closing on our home, I opened a spreadsheet and started logging every extra payment I made toward the principal. It was plain, and at first it was only a record. What I did not expect was what the tracking itself did to me. The more I could see the progress, the more committed I became to making another extra payment. The spreadsheet was not just measuring behavior anymore. It was quietly shaping it.
At some point I caught myself thinking: if this visibility is doing this much for me, why not build something other people on the same journey can use too? That thought never left.
How PayOff Pro Went From Idea to App Store in Four Months
PayOff Pro took about four months to build using Claude Code, an AI coding assistant. It went live on the App Store in November 2025. The core promise was simple: turn the behavior-change loop I discovered in a spreadsheet into something anyone with a mortgage could carry in their pocket.
The moment I could see in real time how much interest I was saving and how many years I was shaving off the mortgage, tracking stopped being a task. It became the reason I wanted to do more.
I should be honest about one thing, though. The version of PayOff Pro on the App Store today was not without hiccups. When I first started, I went straight into Claude Code with nothing but excitement and an idea, with an Excel tracker as my only reference point. I had no product requirements document. No design specs. No version control. I did not even know those things existed yet.
The project kept growing, with errors and unfixable UI problems, until I had to discard the entire thing and restart from scratch. Two solid weeks of coding and tokens wasted. That was painful. But it was also the moment I learned the real lesson: the hard part of building with AI was never going to be the code. The hard part was the clarity, the planning, and the discipline I brought to the table before I ever opened the terminal.
Today, I would not open the terminal on a project without a PRD, a design spec, and a version control setup in place first.
Stop guessing. Start seeing your payoff date move.
PayOff Pro shows you, in real time, how every extra payment changes your interest saved and your freedom date. That visibility is the same behavior-change loop that started this whole story.
[Download PayOff Pro for iPhone →][1]
Your mortgage data never leaves your device. Free to try.
What Mortgage Tracking Taught Me About Behavior Change
Most homeowners know their monthly payment. Far fewer know what their mortgage actually costs them over the full term, and almost none of them watch that number move week by week.
Here is why tracking matters. Consider a standard example — a $400,000 loan at 5.625% interest on a 30-year term. The monthly principal and interest payment works out to about $2,302. If you follow the default schedule and never add a dollar extra to the principal, you will pay roughly $429,000 in interest over the life of the loan. The interest alone is larger than the original loan.
Now change one thing. Apply an extra $300 per month directly to the principal:
Loan: $400,000 at 5.625%
Regular monthly P&I: ~$2,302
Extra principal: $300/month
Estimated time saved: ~7 years
Estimated interest saved: ~$130,000
Double that extra amount to $500 per month:
Loan: $400,000 at 5.625%
Regular monthly P&I: ~$2,302
Extra principal: $500/month
Estimated time saved: ~9 to 10 years
Estimated interest saved: ~$175,000
Those are estimates and they vary with your exact loan terms. But the point is the same one the spreadsheet taught me. Numbers this large are abstract until you can see them move. The moment you can watch interest saved tick up and the freedom date tick closer, extra payments stop feeling like sacrifice and start feeling like progress. That is the behavior change PayOff Pro is built to trigger.
https://youtu.be/ys7FZobg9ws?si=R9qq1NJB0QfaJXLF
The Three Apps That Followed (And Why They All Started With a Pain Point)
Once PayOff Pro was live, something shifted. I had proven to myself that I could take a real problem, plan it out, and ship a finished product. That confidence opened the door to the next one.
On Christmas Eve 2025, I started my second app, Hindsyt. Hindsyt is a decision journal inspired by the Adinkra symbol [Sankofa][2] — the idea of going back to retrieve what you have learned from past mistakes so you can move forward better. I built it because I wanted a way to look at my own decisions honestly and spot the patterns I kept repeating. A few weeks later, Hindsyt was on the App Store.
Next came MeanIt, a mindful spending companion rooted in [Kakeibo][3], a Japanese household finance philosophy created by Hani Motoko in the early 1900s. The core idea is simple but powerful: instead of looking at where your money went after the fact, pause and ask yourself why you are spending before you spend. That shift from autopilot to intention is what MeanIt is built around.
Then came ShowUp. ShowUp started because I realized I had a close friend living in the UK whom I had not contacted in over a year. I wondered if I could build something that would keep me grounded in the relationships that actually mattered, without fail. ShowUp is inspired by Akan philosophy — the idea that personhood is not something you are born with, it is something you earn through your relationships and how you show up for the people around you.
None of them started with me wanting to build an app. They started with me wanting to solve a real pain point in my own life. The app became the vehicle because AI made it possible for someone like me, with no coding background, to actually build it.
What I Would Tell Anyone Sitting on a Spreadsheet Idea
The barrier to creating things has fundamentally changed. It is no longer about whether you can write code. It is about whether you have the clarity to know what you want to build, and the discipline to plan and iterate until it becomes real.
If you are sitting on a spreadsheet, a note on your phone, or a recurring frustration in your daily life, that is not a small thing. That is raw material. Pick one pain point in your own life — something small and specific — and start iterating on it with AI until you resolve it. That is how PayOff Pro got built. That is how all four of the apps got built.
And once you solve something personal, take that same approach into your day job and start improving the workflows that slow your team down. That is where the real leverage shows up, because AI fluency is now a skill set employers are actively looking for. The people who will stand out are the ones who did not wait to be trained. They went out and solved problems on their own first.
Conclusion: Key Takeaways
What you learned:
- ✓ Tracking changes behavior — seeing your payoff progress move is the fastest way to stay committed to extra payments.
- ✓ A good tracker pays for itself — on a $400,000 loan at 5.625%, an extra $300 per month can save roughly $130,000 in interest and cut about 7 years off the term.
- ✓ Clarity beats code — the hard part of building with AI is planning and discipline, not writing the code itself.
- ✓ Start with one real pain point — every useful app I have shipped started with a problem I was living with personally.
Mortgage freedom is different for every person. But the first step is the same one I took in that original spreadsheet: make the progress visible, and let the visibility do the work.
Ready to See Your Payoff Date Move?
PayOff Pro takes the same behavior-change loop that got me out of autopilot and puts it on your home screen. No more guessing where you stand on a 30-year loan.
What you get:
- ✓ Real-time interest saved and freedom-date tracking with every extra payment
- ✓ A clean amortization view that shows exactly where each dollar goes
- ✓ Multiple-strategy comparison so you can test bonuses, windfalls, and round-ups before you commit
- ✓ Full privacy — your mortgage data never leaves your device
3-day free trial. Your mortgage data stays on your iPhone. Built by a homeowner, for homeowners.
Disclaimer: Calculations are estimates for illustration purposes and may not reflect your exact loan terms. Consult your lender for precise figures. This content is educational and not financial advice. PayOffPro helps you track your mortgage; always verify important financial decisions with your lending institution before taking action.