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Key Takeaways
- Heart Monitor integrated 9 wearable providers (Garmin, Polar, Whoop, Apple Health, Samsung Health, and more) using Open Wearables, going from decision to production in weeks.
- At 100,000+ active users, closed platforms like Terra and Rook would cost $10,000-$50,000/month. With Open Wearables, Heart Monitor pays only for infrastructure: roughly $200-500/month regardless of user count.
- All user health data stays on Heart Monitor's own infrastructure. No third-party cloud. Full compliance control.
- Momentum handled integration scoping, OAuth configuration, data normalization, and production deployment, so the Heart Monitor engineering team could focus on product features.
Is Your HealthTech Product Built for Success in Digital Health?
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Most health apps hit the same ceiling. Users show up with data spread across Garmin, Polar, Apple Health, Whoop, and three other devices. Your product can't read any of it. So users manage five apps instead of one, your engagement numbers reflect that fragmentation, and the health intelligence layer you've been building has nothing reliable to work with.
For Heart Monitor, a health monitoring app with 500,000+ downloads and 100,000+ active users on Google Play, this wasn't a theoretical problem. Users were asking directly: why isn't my Garmin data in the app? The team knew what they needed to build. The question was how to build it without spending six months on OAuth plumbing, and without signing a contract that would cost more per month than most engineering salaries once they hit scale.
Why They Chose Open Wearables Over Building From Scratch
Supporting nine wearable providers means nine separate OAuth implementations. Each provider runs its own authorization server, with its own token expiry logic, its own refresh flow, and its own edge cases around revocation and re-auth. Beyond OAuth, each provider has a different data model. Garmin structures activity data differently from Apple Health. Polar's sleep data fields don't map cleanly to Whoop's.
Commercial platforms exist to solve exactly this problem. Terra, Rook, Sahha, and others offer unified APIs with managed OAuth and pre-normalized schemas. For a small team or an early prototype, the economics can work. For a product at Heart Monitor's scale, they don't. At 100,000 active users, per-user pricing on closed platforms runs $10,000-$50,000/month depending on the provider and tier.
There's a second problem beyond cost: data routing. Sending user biometrics through a third-party cloud creates compliance surface area. Heart Monitor's users are sharing sleep data, heart rate variability, and workout metrics. That data doesn't belong in someone else's infrastructure.
Open Wearables addressed both problems directly. It's self-hosted via Docker Compose, which means all user data stays in Heart Monitor's own infrastructure. The cost model is fixed: Heart Monitor pays for their own servers, not per-user access fees. At 100,000 users the infrastructure cost is roughly $200-500/month.
As the Heart Monitor founder put it: "We looked at Terra and Rook. The pricing model just doesn't work when you have a large user base. With Open Wearables we were up and running in days and we own the whole stack."
How the Integration Works
Open Wearables is built on FastAPI, PostgreSQL, Redis, and Celery, deployed via Docker Compose. The architecture sits between your users and the wearable provider APIs, handling the authentication and sync layer so your application backend only needs to talk to one normalized API.
- A user opens Heart Monitor and chooses to connect their Garmin account.
- Heart Monitor's frontend redirects to the Open Wearables OAuth endpoint for Garmin.
- Open Wearables handles the full Garmin OAuth flow and returns a session reference to the Heart Monitor backend.
- Celery workers begin syncing Garmin data on the configured schedule, handling token refresh automatically as credentials expire.
- Heart Monitor's backend reads activity, sleep, and heart rate data from Open Wearables via normalized REST endpoints. The same endpoint structure works regardless of provider.
- Heart Monitor's health intelligence layer receives clean, consistent inputs with no per-provider parsing logic in the application code.
As the Heart Monitor founder described it: "Health data is personal. We needed a solution that kept everything on our own infrastructure, not in someone else's cloud. Open Wearables gave us full control, no vendor lock-in, and zero cost per user."
What Momentum Delivered
Integration scoping. Momentum reviewed Heart Monitor's existing backend to map the data flow, scoping the integration to deliver usable outputs rather than a generic wearable data dump.
Provider configuration. Momentum configured OAuth flows, token refresh logic, and sync schedules for all nine providers. Each configuration was tested against real device data, not mock responses.
Data normalization. Momentum mapped all provider-specific formats to the normalized Open Wearables schema and validated that Heart Monitor's health intelligence layer received consistent, clean inputs from every connected device.
Production deployment and monitoring. Momentum deployed the Open Wearables stack on Heart Monitor's infrastructure and set up post-launch monitoring for sync health and provider API reliability.
Results
Nine wearable providers are now live in production: Garmin, Polar, Suunto, Whoop, Strava, Apple Health, Samsung Health, Google Health Connect, and more. More than 100,000 active users can connect their devices from inside the app.
The cost comparison at this scale is significant. Closed platforms at 100,000 users run $10,000-$50,000/month. Heart Monitor's infrastructure cost with Open Wearables runs $200-500/month. Over twelve months, that's a difference of roughly $115,000-$595,000.
All user health data remains in Heart Monitor's infrastructure. There's no third-party cloud exposure, which simplifies the compliance picture substantially for a product handling personal biometric data.
As the Heart Monitor founder put it: "Our users kept asking why their Garmin data wasn't in the app. Now it is. People want one place for their health data, and they don't want to manage five different apps to get there."
For technical details on how Open Wearables works, see the documentation.
Frequently Asked Questions
Open Wearables is an open-source self-hosted API for wearable data integration. It connects to 9 wearable data providers and 300+ devices (Garmin, Polar, Whoop, Apple Health, Samsung Health, Google Health Connect, and others), handles OAuth flows and token management per provider, normalizes data from different devices into a consistent schema, and exposes it through a single REST API.
It's built on FastAPI, PostgreSQL, Redis, and Celery, deployed via Docker Compose. Because it's self-hosted, all user health data stays on your own infrastructure. See the documentation to get started.
Open Wearables is free and open-source. You pay only for your own infrastructure. At 100,000 active users, infrastructure costs run roughly $200-500/month.
Commercial platforms like Terra and Rook use per-user pricing models. At 100,000 users, those models typically cost $10,000-$50,000/month depending on provider and tier. The cost difference compounds significantly at scale and is the primary driver for teams choosing Open Wearables over managed platforms.
Open Wearables currently supports 9 data providers covering 300+ devices: Garmin, Polar, Suunto, Whoop, Strava, Apple Health, Samsung Health, Google Health Connect, and additional providers.
Data types covered include activity (steps, calories, distance), sleep (stages, duration, quality scores), heart rate and HRV, workouts, and GPS tracks depending on device capabilities. The provider list continues to grow as the open-source project adds new integrations.
Yes. Open Wearables is fully self-hosted via Docker Compose. All user health data — OAuth tokens, synced activity data, sleep records, heart rate data — is stored in your own PostgreSQL database on your own infrastructure. No data routes through third-party clouds.
This gives you full control over data residency and simplifies HIPAA and GDPR compliance, since you define the data handling policies rather than depending on a vendor's terms. See the documentation for deployment instructions.
With Momentum's integration support, most Open Wearables deployments go from decision to production in a few weeks. The scope includes backend review and integration scoping, OAuth configuration and testing for each provider, data normalization validation, and production deployment with monitoring.
The timeline depends on the number of providers, the complexity of the existing backend, and whether data normalization to application-specific schemas requires custom mapping work. Book a demo to discuss your specific architecture.
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