FibonacciGolf: I Built an iOS App in a Day Because Golf Math Got Out of Hand
We were out on the course — four guys, a sunny afternoon — and someone suggested a side bet. Nothing crazy: a buck a hole into the pot, winner takes it. The usual.
Except instead of resetting after every hole, someone suggested letting the pot carry on a tie. And then someone else said the next hole should cost more. And then someone said "what if we do Fibonacci?" — and suddenly we were doing mental math on the 7th tee trying to figure out what happens when you tie three holes in a row starting at two dollars a person.
I put my phone down long enough to pull out my notes app and do the arithmetic. It got old fast. By the back nine I'd sketched out an app in my head. By that evening I was building it. By the next morning FibonacciGolf was functional. It's now live on the App Store.
How the bet works
The idea is simple: everyone antes the same buy-in into a shared pot on each hole. Win the hole outright and you take the pot. Tie the hole and the pot carries forward — but the next buy-in climbs to the next number in the Fibonacci sequence: 1, 2, 3, 5, 8, 13, 21… each rung is the sum of the previous two.
One clutch hole can swing the whole round. A run of ties is genuinely exciting — the pot balloons and everyone feels it.
The app supports two flavors of the game:
Flat Start — the classic. The buy-in stays at the base each hole; a tie climbs the ladder, but the next win resets it back to the base. Stakes spike on runs of ties and reset after every settled hole.
Full Climb — the relentless version. The buy-in climbs every single hole regardless of outcome. A win takes the pot but the ladder never resets.
There's also a pot-rollover toggle: with rollover off, a tie is a push — the money doesn't move and the ladder resets. With rollover on (the default, more interesting version), the pot carries and the ladder climbs.
Setting up a round
You open the Play tab, add your players (tap from your friends list or just type a name), pick a starting buy-in from a preset or type your own, choose Flat Start or Full Climb, and go. That's it. The app handles all the arithmetic as you tap through each hole.
At any point you can see the live standings and a settle-up view that keeps "who pays whom" as simple as possible. No math in the parking lot.
Your round history
Every round is saved with its name, course, and date. You can search through past rounds, open any of them to see the full hole-by-hole scorecard and final standings, and edit any hole after the fact — the app re-scores everything correctly. Deleted rounds go to a 14-day trash so nothing's lost by accident. If the round ends with money still on the table — the classic "we tied 18" — you can bank the live pot into a new round so it's settled next time.
Playing with the group
Adding a friend is one tap: Profile → Friends → Add a friend. The app hands you a personal invite link to text to whoever you want. They tap it, you're both connected — instantly, across any two phones, with no account and no sign-in required on either side. (Identity is an anonymous random ID generated on each device; no email or photo leaves the phone.)
When you start a round you can turn on "Share with the group." Everyone in the group follows the same live scorecard on their own phone and gets a notification — "Ann won $24 on hole 3" — as the round unfolds.
After a round you can share a crisp portrait image of the scorecard for the group chat, or send a link that opens the round in anyone's app as their own editable copy.
Built in a day
The core of the app — setup, scoring, the Fibonacci engine, offline storage — was done the day after the round. The social features (friends, shared live games, the fibonaccigolf.com backend) came in the next couple of weeks as I realized the group-chat sharing was the part everyone actually wanted.
It's a native iPhone app, written in Swift. Rounds live on your device and work fully offline. The optional social layer runs through a small first-party service at fibonaccigolf.com — no iCloud, no third-party accounts, nothing required beyond opening the app.
There's a built-in How to Play tab so a new group can get going without anyone having to explain the rules. And a Profile tab where you can set a name, motto, and photo — or just let your initials avatar do the talking.
Free, no ads, private
FibonacciGolf is free with no in-app purchases. No ads, no trackers, no third-party analytics. The only thing the social service ever stores is your display name and a random ID — nothing else leaves the device. It never handles real money; it just keeps score and tells you who owes whom so you can settle up in person.
iPhone only, iOS 17 and later. Available in the United States, Canada, and Mexico.