Live-Streamed Fitness Classes with Wearable Integration
A cross-platform fitness app where a user can join a live yoga class with real-time video and chat, have that class automatically saved to their history for later replay, and see their heart rate and calories update live on their wrist throughout the session.
FitFusion lets instructors run live yoga and fitness classes that feel like a real studio session. Users join a live class with an instructor, see and chat with other participants in real time, and can revisit any past live session on demand from their profile history afterward — with heart rate and calories updating live on their Apple Watch throughout.
Fitness apps are either static or laggy — neither feels like a real class.
Pre-recorded video libraries are convenient but static, with no live instructor cueing and no sense of other people in the room. Apps that attempt live classes often suffer from video lag or chat that trails seconds behind the video, breaking the illusion of a shared live session.
- Real live classes, not just scheduled video playback
- In-class social presence with live chat during the session
- Nothing live should be a one-time-only event — every class available for replay afterward
- Real biometric feedback during the workout, not a post-workout summary
How we built it.
React Native for a single cross-platform codebase
iOS and Android shipped from the same team on the same timeline, with native modules layered in only where a capability like Apple Watch/HealthKit required it.
Agora for real-time video and chat
FitFusion's live class experience runs on Agora's real-time engine, using low-latency video channels for the class stream and real-time messaging for in-class chat on the same backbone.
Automatic session recording
Every live class channel is recorded as part of the session lifecycle itself, so a class landing in a user's profile history is default behavior, not an opt-in feature.
Native Apple Watch companion via HealthKit
Heart rate and calorie data are read from the Apple Watch during an active session and streamed to the phone app in real time.
The solution.
Live classes with synced video and chat
Instructors run live sessions over Agora's real-time video channels; participant chat rides the same real-time backbone, staying in step with what's happening on screen.
Automatic on-demand replay
Every live class is recorded as part of the session lifecycle and automatically appears in each participant's profile history afterward.
Live Apple Watch biometrics
A native watch companion reads heart rate and calorie burn from HealthKit throughout an active class and streams it to the phone app in real time.
Cross-platform core, native where it counts
The full class-browsing, joining, chat, and profile-history experience is one React Native codebase; the Apple Watch integration is a native iOS-specific capability layered on top.
Profile history as a first-class feature
Past live classes live in the user's profile as a real, browsable history of every session attended, live or replayed.
Outcomes that shipped.
Users could follow an instructor's real-time cues without the lag that pushes people toward pre-recorded video in comparable apps. No live class was ever a one-time-only event — every session became part of a user's on-demand replay history automatically, and Apple Watch users could see their own effort update live alongside the class. Validated a real-time video + chat + wearable integration pattern reusable for other live-class or live-social fitness products.
What we took with us.
- 01Earlier testing under weaker real-world network conditions would have caught edge cases sooner — Agora performed well in typical conditions but a deliberate weak-network test pass should have come earlier.
- 02More proactive instructor-side tooling for trimming or marking sensitive segments of a recording should have shipped sooner rather than maturing after launch.
- 03Android wearable parity considered sooner — the initial wearable integration was Apple Watch/iOS-specific; a comparable Wear OS integration would extend the same experience to the full user base.
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