RND20 iOS workout app

The goal was to turn a simple, effective workout format into a focused, trustworthy mobile experience. The app had to:

• run a single 20-minute countdown that stays readable in the middle of a workout,
• let users log rounds with one tap, without navigating away from the exercise,
• track personal bests, weekly sessions and lifetime workouts,
• support sharing, friends and direct challenges to keep users motivated,
• offer a Pro tier with Live Activities, Apple Health and Apple Watch integration,
• be released and distributed through the Apple App Store.

I built the app with Expo, allowing one codebase to cover iOS, Android and web while still reaching native iOS features. The result is a fast, focused workout companion:

• Live timer and round counter — a large, legible 20-minute countdown and a single button to log completed rounds.
• Expo cross-platform foundation — one shared codebase for the landing page at rnd20.eu, the web app at app.rnd20.eu and the iOS app.
• Apple Watch app — users can follow and log rounds from their wrist during the workout.
• Live Activities on the Lock Screen — the Pro tier keeps time and rounds visible without unlocking the phone.
• Apple Health integration — finished workouts can be written to Health for users who want to keep everything in one place.
• Friends and challenges — add friends, compare scores and send direct challenges to beat a number.
• App Store distribution — the app is built, signed and published for the Apple App Store, including paid Pro subscriptions.

RND20 became a real, end-to-end mobile product: a marketing landing page, a responsive web app and a native iOS app sharing the same code and design. The App Store release means the app can reach iPhone and Apple Watch users directly, and the Pro tier opens a straightforward path to paid features without complicating the core free workout.

Native iOS features from a shared codebase. Expo makes it possible to offer an iOS app, Apple Watch support and Live Activities without maintaining three separate projects.

UX built for the middle of a workout. Large numbers, one-tap logging and no hidden menus mean the app gets out of the way when the user is out of breath.

Clear commercial path. The core workout stays free, while the Pro tier adds Apple-specific features and is delivered through the App Store with a simple subscription.