Atreus: Gym Workout Log

Inspiration

I’ve always wanted to use a gym app that was actually useful, simple yet deep, and beautiful and elegant. The only thing I’ve found are apps where the interesting features are behind a paywall, with horrible aesthetics, and focused on superficial, non-science-based training.

What it does

My app is just that: an app that works perfectly while being free, where you can access interesting additional paid options without resorting to the mutilation of the app, featuring an elegant design, and with enough depth to keep progressing even if you are an advanced lifter.

How we built it

We built the app using React and TypeScript for a robust, type-safe frontend, paired with Zustand for clean and lightweight state management. On the mobile and backend side, we leveraged Kotlin, JavaScript, and Supabase for database management and core authentication, along with Google Cloud to handle seamless Google OAuth sign-ins. Finally, we integrated RevenueCat to smoothly manage in-app subscriptions and purchases.

Challenges we ran into

The primary challenge was managing the complexity of generating mesocycles tailored specifically to each user’s needs. This included calculating dynamically adjusted exercise weight ranges based on user performance averages, as well as enabling our AI Coach (Pro version) to accurately interpret all of this data to configure personalized mesocycles, select smart alternative exercises, and make real-time progression adjustments.

Accomplishments that we're proud of

The overall performance and functionality of the app have been incredible. I didn't realize I would be capable of building all of this on my own! On top of that, I already have my first paid subscriber, and they are loving the experience.

What we learned

I’ve learned an immense amount about all these technologies along the way. Beyond the code, I’ve also continued deepening my understanding of the science behind strength training—a subject I’ve been truly passionate about for years.

What's next for Atreus: Gym Workout Log

The next step is adding brand new Pro features. Down the line, I would also love to create custom, proprietary exercise animations from scratch—no buying the same generic 3D animations every other app uses.

Built With

• google-cloud
• javascript
• kotlin
• react
• revenuecat
• supabase
• typescript
• zustand