Tren - Train Smarter & Better

Get coached. Or coach yourself.

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Inspiration

Tren started as my final-year university venture project. The question behind it was simple:

How might we make fitness coaching more accessible, interactive, and affordable?

We looked at the problem from both sides. Clients wanted personal guidance but usually found coaches through word of mouth or Instagram ads, with no way to tell who was actually good. Coaches were running their businesses across spreadsheets, WhatsApp, and email, with no easy way to find new clients or prove their credibility.

The coaching platforms that already existed mostly served coaches and were priced out of reach for newer gym-goers. That gap, affordability, became our focus.

The project earned seed funding from SUTD's BabyShark Fund, but it required at least one team member to still be enrolled. Once we all graduated, the venture had to stop.

I picked it back up while working full-time, first as the project I used to teach myself SwiftUI, and then as something I decided to pursue seriously as a solo indie developer. Shipaton is my push to turn it into real, shipped software, with a working subscription model that actually charges a card.

What it does

Tren is an iOS marketplace that connects independent fitness coaches with clients.

For clients

  • Search for coaches by speciality and see which ones are identity-verified
  • Chat with coaches directly in the app
  • Build your own workouts, routines, and custom exercises
  • Train with the TREN AI Workout Buddy, a real-time companion built with Apple's Foundation Models framework. It looks at your previous performance, current set, target reps, and chosen intensity, then suggests what to attempt next. The goal is to make progressive overload deliberate instead of guesswork.

The free tier includes the AI Workout Buddy and a generous allowance of routines and exercises. Tren Unlimited is a low-cost subscription that removes those limits and lets you personalize how the AI approaches your training.

For coaches

  • A dashboard of active clients
  • Build and assign workout programs and nutrition plans
  • Run check-ins and message clients, all in one place
  • Get verified with an identity check, so clients know you're who you say you are

Coach plans come in Starter, Pro, and Elite tiers. Higher tiers support more clients, more templates and custom exercises, and include identity verification, which also boosts a coach's visibility in recommendations.

How I built it

  • iOS app: Swift and SwiftUI
  • Auth and database: Supabase
  • Backend: Python FastAPI on Google Cloud Run
  • Subscriptions: RevenueCat (purchases-ios) handles billing, entitlements, and purchase state for both client and coach plans
  • Coach verification: AWS Rekognition, unlocked through the same RevenueCat entitlement as the paid coach tiers

Challenges I ran into

Cutting the pitch deck down to an MVP. The original plan included everything: marketplace, AI chatbot, nutrition, scheduling, commissions, and ads. Shipaton forced me to pick the smallest version that proves the core loop: a client finds a coach, the coach manages that client, and a subscription pays for it. Deciding what to leave out was harder than deciding what to build.

The chicken-and-egg problem. Clients won't stay without coaches, and coaches won't join without clients. My answer is to give clients a reason to use Tren on day one, before they ever hire a coach. The free AI Workout Buddy does that. As the client base grows, Tren becomes more attractive to coaches.

Letting coaches be clients too. A coach can also use Tren to find and train with other coaches, without a second account. That meant designing roles so one account can hold both at once. It's live now, and it means every coach who joins is also a potential client.

Accomplishments that I'm proud of

  • Onboarded 6 coaches onto the platform
  • Reached 23 active users
  • Turned a university slide deck into a live app with working subscriptions on both sides of the marketplace

What I learned

In the AI era, building the product is no longer the hardest part. Getting it in front of the right people is. Anyone can ship an app quickly now, but getting coaches and clients to notice it takes real effort. So my focus is shifting from just writing Swift to learning how to market Tren as seriously as I built it.

What's next for Tren

  • AI-generated templates and workouts, so clients and coaches can create full programs in seconds
  • TREN AI for coaches (targeting 2027): ask questions like "Has Maya's weight been trending down?", summarize check-ins, and draft programs automatically
  • Growing verified coaches and partnering with gyms and fitness centres to bring both sides onto the platform together
  • Bringing Tren to Android, so no coach or client is left out

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