Web · iOS · Android · one monorepo
Gym software locks owners into rigid platforms or forces them to juggle three separate apps — one for scheduling, one for messaging, one for progress tracking. Tengen ships all three in one monorepo: trainer web app, client mobile app, NestJS API, with the routine builder as the hook.
Tengen is a full-stack fitness platform built as a monorepo with NestJS API, React 19 web app, and React Native mobile app. Features drag-and-drop workout routine builder, exercise library (global + custom per gym), real-time push notifications, client progress tracking, multi-gym support, role-based access, offline-friendly mobile app, and Stripe billing with 14-day free trial across three subscription tiers.
React 19 web app, React Native mobile, NestJS API — sharing types and validators via a common package. Client-side validation mirrors the server exactly: one source of truth for form rules.
Workouts stream to the mobile app and persist locally. Athletes can train without connectivity and sync the moment they're back online.
Gym chains with several locations scale without schema rewrites. Owner / trainer / client permissions are enforced at the API.