Garmin API integration through Spike Wearables API

The fitness tracker market is projected to reach $162.8 billion by 2030, with running tracking as the largest application segment, accounting for nearly 23% of revenue. Garmin is the top choice among serious athletes who need advanced training metrics, GPS accuracy, and multi-sport capabilities that consumer smartwatches just don't match.

Building a direct Garmin integration means navigating the developer program, implementing OAuth, handling webhooks, and maintaining the connection as the API gets updated. Multiply that by every other wearable you may also need to add, and you're looking at months of integration work. Relying on aggregators like Health Connect or HealthKit seems easier, but you lose the granular Garmin-specific data that users expect from their premium devices.

Spike Wearables API solves this with a single integration that connects your app to Garmin and 500+ other wearable and IoT devices. You get direct access to heart rate, sleep stages, activity summaries, and Garmin-specific metrics like VO2 max and HRV through a unified API that also supports Fitbit, Whoop, Oura, Apple Health, and hundreds more.

What Garmin data can you access?

Spike API provides a direct Garmin integration and access to metrics in both raw and normalized formats. You can work with Garmin's original data structure or use Spike's unified schema that stays consistent across all 500+ supported devices.

Daily metrics include steps, distance (with breakdowns for running, walking, cycling, swimming, and wheelchair), active and basal calories burned, floors climbed, resting heart rate, HRV (RMSSD), VO2 max estimates, and skin temperature deviation during sleep.

Sleep metrics cover duration with stage breakdowns (deep, light, REM, awake, nap), sleep interruptions, SpO2 levels, and breathing rate throughout the night.

Workout metrics deliver GPS coordinates (latitude/longitude), pace, speed, cadence, elevation changes, ascent/descent, and sport-specific data like swimming lengths. Heart rate zones and SpO2 tracking round out the activity picture.

User properties include weight, body fat percentage, bone mass, and BMI for longitudinal health tracking.

Historical data becomes available immediately when users connect their Garmin accounts. With Spike, you can retrieve a month of past data, with longer periods available case-by-case, giving your app context about training patterns from day one without requiring weeks of active tracking.

Direct integration vs platform aggregators

Many developers consider routing Garmin data through platform aggregators like Apple HealthKit or Google Health Connect. Yet, despite being convenient, they come with serious limitations. For apps targeting athletes and fitness enthusiasts, these tradeoffs directly impact user experience and retention.

Complete data vs normalized subsets

Health Connect and HealthKit only support a limited set of Garmin metrics. Aggregators normalize data across devices, stripping away granular details like distance breakdowns by activity type, HRV measurements, and sport-specific workout data. Garmin-specific metrics are precisely why users choose the device, so losing this granular data means your app can't fully support Garmin users.

Direct integration through Spike provides Garmin's complete dataset, including VO2 max, detailed sleep stages with SpO2 and breathing rate, workout GPS coordinates with elevation tracking, and much more.

Near real-time data vs delayed syncing

Aggregators rely on OS-level background processes with scheduling restrictions. Meaning, users might sync their Garmin, but your app won't receive updates for minutes or hours.

Direct integration eliminates this delay. Garmin's API supports event-driven notifications that deliver data within seconds of device sync. OuiLive reduced support tickets by 40% after switching to Spike's SDK because their corporate wellness users needed immediate data visibility.

Cross-platform consistency

HealthKit only works on iOS, and Health Connect requires Android 14 or newer. Building separate integrations multiplies engineering work and creates inconsistent user experiences.

Spike's direct Garmin integration works identically across iOS, Android, and web with a single integration.

Handling duplicate data

A common challenge emerges when users enable both direct Garmin integration and sync their device to Health Connect or HealthKit. The same workout appears twice in your database.

This can be solved through bundle ID filtering. Spike provides source identifiers with each data point, revealing which app originally wrote the data, so you can filter duplicates and prioritize direct integration data without building manual deduplication logic.

Beyond raw data: AI-powered coaching

Spike delivers Garmin data in both raw and normalized formats, ensuring consistency across device models. Whether your user has a Forerunner 265 or a Venu 3, you receive the same data structure.

However, raw metrics alone don't drive engagement. Users expect apps to interpret their data and provide actionable guidance. The real opportunity lies in connecting this data to Spike MCP. Instead of showing "You burned 450 calories today," your app can analyze sleep quality (SpO2 dips, breathing rate changes), workout intensity, and recovery patterns to provide contextual guidance. For example, an AI coach might correlate declining HRV with increased training load and recommend a recovery day before the user hits overtraining. This transforms basic tracking into personalized health coaching that identifies overtraining patterns, correlates HRV trends with performance, and enables personalized recommendations based on sleep and activity data. 

Getting started

Schedule a demo with Spike's team to discuss how Garmin integration fits your specific use case, or explore how combining wearable data with AI through Spike MCP can differentiate your health and fitness app.