RunnerY

Posted on Jan 28

<Day4>Run or Pay? App building. Done Apple Developer Program & inside TestFlight

#devjournal #ios #showdev #sideprojects

What I’m Building

Users set an amount of money they agree to pay if they fail to run at least 60 minutes within a week, and authorize the payment in advance.
Running time is measured via HealthKit using an iPhone or Apple Watch.
Because money is on the line, users are effectively forced to run, helping build consistent exercise habits.
If the user fails to reach the target, the pre-authorized payment is captured by the service. If the target is achieved, the payment is automatically canceled.

If you try the beta version, I'll send you TestFlight invitation code! Please comment!

The app icon is ready:

Finally completed account registration
Implemented Sign in with Apple
Since the app was designed around Apple ID login from the start, I can now test all features properly on a real device
Added logic to measure running time via HealthKit

Payments are the most anxiety-inducing part when thinking about real-world usage.
So far, I’ve been doing a lot of vibe coding, but payment-related logic needs proper test coverage.
Main concerns:
- Whether the cron job that checks user status and determines challenge completion works reliably
- Whether payment cancellations are handled correctly
I’m also unsure whether Japanese users will feel comfortable making payments via Stripe, which isn’t very familiar in Japan.

The app relies on workouts recorded by external apps, so all of the following need to work correctly:

All of these need to be tested — ideally by real users.

For the MVP, I decided to skip in-app workout tracking, since the implementation and running costs don’t justify it at this stage.