Gymni: an app and platform for personal trainers
Gymni is my own product for personal trainers and their clients: clients find a trainer and book a session, trainers run their schedule, clients, chat and subscriptions in one app. I build the mobile app, the Supabase backend and the website, and run go-to-market.
The problem
Clients should be able to find a trainer and book a session in a couple of taps, and trainers should be able to run their business — schedule, clients, chat, payments — in one place instead of in DMs.
What I did
- Built the mobile app in Expo and React Native: trainer search, booking with available slots, rescheduling and cancelling, schedule, chat, client management, session ratings and invites.
- Built the backend on Supabase: Postgres with 130 migrations and about 80 edge functions for search, bookings, automatic completion of sessions, reviews, reminders and win-back notifications.
- Subscriptions through RevenueCat, including a cancellation flow; chat on Stream Chat; Google Calendar sync.
- The website in English and Ukrainian with invite and trainer-profile links, and contributions to the internal admin panel.
- CI with GitHub Actions and guarded deploys to production.
- Run go-to-market myself: positioning, funnel, content and the first users.
Result
- The app is in beta.
Tech stack
- Mobile
- Expo 55
- expo-router
- React Native 0.83
- React 19
- TypeScript
- NativeWind (Tailwind)
- Reanimated 4
- Zustand
- TanStack Query with offline persistence
- i18next
- Backend
- Supabase Postgres (130 migrations)
- ~80 Supabase Edge Functions (Deno)
- Supabase Auth
- Cron jobs
- Integrations
- RevenueCat subscriptions
- Stream Chat
- Google Calendar sync
- Google Places
- Resend email
- Push via FCM and APNs
- Auth
- Apple Sign-In
- Google (expo-auth-session)
- Secure store
- Observability
- Sentry
- Firebase Analytics
- Crashlytics
- Remote Config
- GA4
- Web
- Next.js 16 landing (EN / UA)
- React admin panel (MUI)
- Vercel
- Quality & delivery
- Jest
- Testing Library
- GitHub Actions CI
- Stage and prod deploy workflows
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