7 min read
Health Connect SDK: 32 Releases, One Stable
Google has shipped 32 connect-client releases since August 2022 and one stable build, 1.1.0. The alpha runs, gaps and cadence, counted from the notes.
health-connectandroidecosystem
AI Fitness API · for builders in health, wellness & fitnessPick the right fitness API.
Pick the right fitness API.
Ship without the surprises.
Wearables, health data, nutrition, AI motion tracking — compared, priced, and documented down to the failure modes, with the deprecations and deadline traps called out before they cost you a rewrite.
- 432+
- verified guides & comparisons
- 24
- fitness APIs in the directory
- 8
- CI-tested code recipes
- CC BY
- open datasets, free to reuse
Fitness APIs at a glance
A fitness API is a service that lets your application programmatically retrieve fitness or health data, or invoke a fitness capability, without building the underlying data pipeline yourself. Most are HTTP/REST web services you call over the network; a key exception is on-device health stores like Apple HealthKit and Google Health Connect, which you reach through the phone's operating system rather than a remote server. It is a category, not a single product: exercise-content databases, wearable-metric APIs, nutrition APIs, AI-motion SDKs, and aggregators are all fitness APIs, each solving a different job. What a fitness API is goes further.
| API | Category | How it bills you | Approval gate | Cost on the user’s side |
|---|---|---|---|---|
| Fitbit Web API (Google) | Wearable APIs (direct) | Free | Yes | Yes |
| Garmin Health / Activity API | Wearable APIs (direct) | Free | Yes | Yes |
| Oura Cloud API | Wearable APIs (direct) | Free | Yes | Yes |
| WHOOP Developer Platform | Wearable APIs (direct) | Free | Yes | Yes |
| Strava API | Wearable APIs (direct) | Free | Yes | Yes |
| Polar Open AccessLink | Wearable APIs (direct) | Free | None documented | Yes |
| Terra | Health-data aggregators | Usage-based | Yes | None documented |
| Junction (formerly Vital) | Health-data aggregators | Usage-based | None documented | None documented |
| Rook | Health-data aggregators | Usage-based | Yes | None documented |
| Spike | Health-data aggregators | Usage-based | Yes | None documented |
| Apple HealthKit | Platform health stores | Free | Yes | None documented |
| Google Health Connect | Platform health stores | Free | Yes | None documented |
| Nutritionix | Nutrition & food data | Free tier | Yes | None documented |
| Edamam | Nutrition & food data | Free tier | None documented | None documented |
| USDA FoodData Central | Nutrition & food data | Free | None documented | None documented |
| Open Food Facts | Nutrition & food data | Free | None documented | None documented |
| ExerciseDB (AscendAPI) | Exercise content | Free tier | None documented | None documented |
| wger (self-hosted) | Exercise content | Free | None documented | None documented |
| KinesteX | AI motion / coaching SDKs | Contact sales | Yes | None documented |
| Sency (SMKit) | AI motion / coaching SDKs | Usage-based | Yes | None documented |
| QuickPose | AI motion / coaching SDKs | Free tier | None documented | None documented |
| MediaPipe Pose Landmarker (BlazePose) | Pose-estimation models | Free | None documented | None documented |
| TensorFlow MoveNet | Pose-estimation models | Free | None documented | None documented |
| Apple Vision body pose | Pose-estimation models | Free | None documented | None documented |
Each row opens the product’s entry in the fitness API list, with what each gate and cost is and every page here that covers it, or compare any two side by side. “None documented” means none in the sources we checked, not that none exists. KinesteX funds this site and is listed by the same rule as every other product.
Start where you are
I’m choosing an API
Compare the field by the job you’re hiring for — data coverage, pricing model, approval gates — before you write a line of integration code.
I’m building AI features
Camera rep counting, form feedback, LLM coaching — the whole pipeline from pose model or SDK choice to guardrails, latency, and cost.
Something broke — or a deadline looms
401s, dead webhooks, empty reads — symptom-to-fix pages. And when a platform is being retired, the dated migration playbook is already written.
Handed a whole job rather than one question? 4 reading paths put the pages for one task in working order, with a sentence per step on why it comes there.
Popular APIs & SDKs
All integration guides →Apple HealthKitOn-device · iOS
No OAuth, no servers — and read-denial is invisible by design. The full Swift integration guide.Read the guide Health Connect APIOn-device · Android
The successor to Google Fit on Android: permissions, the 30-day read window, and the quirks.Read the guide Fitbit Web APITurns off Oct 30, 2026
Widely integrated; Google turns the legacy API off on October 30, 2026. The guide, plus the migration path to Google's cloud API.Read the guide Strava APICloud · OAuth
Activities, segments, and webhooks — under developer terms that have tightened. What's still allowed.Read the guide Garmin APICloud · approval-gated
Deep wearable data behind a developer-program approval. How to apply, integrate, and pass review.Read the guide Oura APICloud · OAuth
Sleep, readiness, and HRV from the ring — including the personal-access-token deprecation.Read the guide WHOOP APICloud · OAuth
Recovery, strain, and sleep via OAuth — and what changed in the developer platform restructure.Read the guide TerraAggregator
One integration, many wearables. When an aggregator earns its fee — and when direct is better.Read the guide Polar API (AccessLink)Cloud · OAuth
Training, sleep, and recharge data from Polar devices — registration through webhooks.Read the guide Exercise video APIsExercise content
Which exercise APIs serve demonstration video, and which stop at GIFs or still images.Read the guide NutritionixNutrition
Natural-language food logging and a large verified food database — pricing model included.Read the guide MediaPipe, MoveNet & pose modelsOpen-source models
The open pose-estimation stacks compared: accuracy, platforms, and maintenance status.Read the guide AI motion SDKsKinesteX · Sency · QuickPose
Camera-based rep counting and form feedback as a product decision: build on models or buy an SDK.Read the guide Free tools — no signup needed
API Directory
One page per API: how it bills you, what your users must own, what gates launch.
Browse itAPI Picker
Three questions, a tailored recommendation with next steps — and the reasoning shown.
Try itCost Planner
Model what your stack costs at your user count — every price traced to its source.
Plan costsType Matrix
Every metric’s HealthKit ↔ Health Connect type — and where they quietly disagree.
Open itDay-Boundary Demo
Watch a naive daily rollup break on DST and timezones — interactively, then fix it.
See it breakError Diagnoser
Paste an error string; get the matching HKError.Code case in Apple’s wording, plus the guide that covers it.
Diagnose itStack Generator
Answer four questions; get the HealthKit types and APIs that survive them, with the exclusions shown.
Generate itAll Free Tools
Plus the aggregation checker, identifier translator, permission builder and query generator — all on one page, all running in your browser.
See every toolReference — read from the platforms’ own documentation
Generated, not written. Every value below is read from Apple’s documentation JSON or verified against both platforms’ docs, and regenerating the dataset updates every page that cites it.
HealthKit, mapped
All 241 identifiers across 12 group pages — the unit each comes back in, whether you sum or average it, iOS availability, and the Health Connect record where one is verified.
Open the referenceAll 241 HealthKit types
Quantity, category, characteristic and workout identifiers — with units, availability, and whether you sum or average each one.
Open the referenceAll 17 HealthKit errors
What each failure means — including why a denied read raises no error at all, and returns an empty result instead.
Open the referenceHealthKit ↔ Health Connect
The cross-platform mapping for the metrics we verified on both, and the pairs that look equivalent but are not.
Open the referenceAlso in the reference: HealthKit by iOS version · Health Connect record reference · Every Health Connect permission · Open-source health libraries
Verified in the last 30 days
The full tracker →193 of 432 pages were re-checked against their sources in the last 30 days, and these are the most recently verified entries in the changes tracker. Both numbers are computed at build time from the pages themselves — if we stop doing the work, this section says so.
Everything we cover
Fitness & workout APIs17 guides
Compare and choose an API by the job — exercise content, wearables, aggregators, nutrition, or AI motion tracking.Newest verified 2026-10-22Add AI workout tracking11 guides
The capture → pose → interpret pipeline: camera pose, rep counting, form feedback, and per-platform wiring.Newest verified 2026-10-18Build a workout app24 guides
End-to-end build playbooks by app type — home workout, coaching, strength, running, rehab, and more.Newest verified 2026-09-04Integration guides23 guides
Register, OAuth, fetch, and webhooks — a hands-on guide per provider, from HealthKit to Terra.Newest verified 2026-10-22Troubleshooting30 guides
Symptom-to-fix for the common errors: 401s, rate limits, empty data, dead webhooks, and OAuth snags.Newest verified 2026-10-22Concepts explained13 guides
Plain-English explainers for the health-tech vocabulary — OAuth, aggregators, HRV, VO2 max, and more.Newest verified 2026-08-12Alternatives23 guides
Anchored on one product: why teams look to switch, and the realistic options — with links to the comparisons.Newest verified 2026-10-27Compliance & privacy23 guides
Which rules apply — HIPAA, GDPR, FDA, app-store policy — and how to build for consent, storage, and deletion.Newest verified 2026-10-17Migration guides11 guides
Step-by-step playbooks for moving an integration — Google Fit to Health Connect, direct-to-aggregator, and more.Newest verified 2026-10-12Pricing20 guides
What fitness and health APIs really cost — which are free to call, which charge, and what drives your bill.Newest verified 2026-10-27Comparisons27 guides
Head-to-heads through the developer lens — Oura vs WHOOP, Fitbit vs Apple Watch, Terra vs Rook, and more.Newest verified 2026-10-27Health data by metric29 guides
Which API gives you each metric — heart rate, steps, sleep, calories, HRV, VO2 max — and measured vs estimated.Newest verified 2026-10-18AI motion & pose estimation28 guides
The tech behind camera fitness — pose models, 2D vs 3D, on-device vs cloud, rep counting, and form scoring.Newest verified 2026-10-18AI & LLM features12 guides
Plan generation, natural-language food logging, coaching prompts — plus guardrails, model choice, and cost.Newest verified 2026-10-17Health data architecture15 guides
The layer after the integration works — dedupe, normalization, timezones, sync, storage, and data quality.Newest verified 2026-08-12Testing health apps14 guides
HealthKit has no test double, CI cannot fire background delivery, the simulator has no camera. What to do instead.Newest verified 2026-10-02Cookbook: tested code8 guides
Runnable, dependency-free reference implementations — token rotation, webhooks, DST-safe rollups — CI-tested.Newest verified 2026-10-02Connected devices12 guides
Straps, treadmills, trainers, and the watch as a live sensor — BLE heart rate, FTMS, and the testing story.Newest verified 2026-08-14Engagement & retention17 guides
Getting people back: notifications, Live Activities, widgets, streaks, leaderboards — and measuring lift honestly.Newest verified 2026-10-03Watch apps17 guides
Writing the app on the wrist: workout sessions, background execution, WorkoutKit, Wear OS tiles, battery, testing.Newest verified 2026-10-03Accessibility12 guides
Screen readers over live workout metrics, text scaling, touch targets, contrast outdoors, reduced motion, haptics, captions.Newest verified 2026-08-22Audio coaching12 guides
Workout cues over the user's music: ducking, interruptions, background audio, Android audio focus, TextToSpeech, watch speakers.Newest verified 2026-10-03HealthKit query classes9 guides
HKSampleQuery, statistics, anchored and observer queries, async descriptors, routes and rings: how each works and where it bites.Newest verified 2026-10-03Phone sensors10 guides
Steps, activity, altitude and AirPods head motion from the phone itself: CMPedometer, Android step sensors, activity transitions, health permissions.Newest verified 2026-10-03Health Connect API15 guides
The Jetpack API method by method: readRecords paging, aggregates, getChanges, clientRecordId upserts, permissions, background and history reads.Newest verified 2026-10-04Why builders trust this site
Sourced, or it doesn’t ship
Every price, limit, and deadline traces to a primary source checked when the page was written. When we can’t verify a claim, the page says so instead of rounding up to certainty. How we verify →
Dates graded, not sharpened
The changes tracker labels every deadline confirmed — vendor’s own words, quoted — or reported, and keeps each date at the precision its evidence supports. See the tracker →
Code that actually runs
Cookbook recipes are dependency-free files with node:test suites, run in CI on every change — the code on the page is a byte-verbatim copy of the file that passed. Open the cookbook →
Funding, disclosed
KinesteX, an AI motion SDK, funds this site. Every page that features it says so in a banner like this one, our comparisons list where its competitors win, and nothing here ever crowns the sponsor. Read the rules we follow →
Annual report
The State of Fitness APIs 2026
The year the free ride ended: shutdowns, paywalls, and model freezes across the ecosystem — what changed, what it costs now, and where the risk sits next.
Read the report →The data behind it is open
Pricing, access models, and status for the ecosystem in one dataset — CC BY 4.0, so you can cite it, load it, or build on it.
Dated changes, latest first — as of October 27, 2026
Full tracker →December 2026confirmed
Google Fit APIs: end of documented supportGoogle's Fit migration guide on developer.android.com (updated September 10, 2026) states "The Google Fit APIs will be supported until the end of 2026" — end of support, with no switch-off date published. It recommends the Google Health API for cloud-based integrations (including the Fit History and Session APIs), Health Connect for step tracking and mobile-first apps, and Health Services on Wear OS, and lists no replacement for the Goals API.Google Fit shutdown hub November 3, 2026confirmed
Terra legacy widget endpoint deprecationTerra relaunched its connect widget. Its documentation says the older session endpoint, POST https://api.tryterra.co/v2/auth/generateWidgetSession, "keeps working today, with deprecation planned for 3 November 2026", and that "Accounts created after 3 September 2026 cannot use it at all." New sessions are created at POST https://access.tryterra.co/api/widget/session; the response shape (session_id, url, status, expires_in) is unchanged, while the multi-provider and all-providers options are now sent differently.How to integrate Terra October 30, 2026confirmed
Fitbit Web API turn-offGoogle's Google Health API page states that on October 30, 2026 "the Fitbit Web API will be turned off and will no longer function or sync data to or from Fitbit users", and that all current integrations "must migrate their applications and users to the Google Health API and Google OAuth 2.0 as soon as possible". Until then the legacy API keeps operating without support, and Google's migration guide has apps support both login methods while it does. Existing tokens cannot be transferred, so every user re-consents through Google OAuth.Fitbit API shutdown center When a reported date firms up or a term changes, subscribers hear first — with the source, not the panic. Join them below ↓
Latest writing
View all →7 min read
Health Connect Has 219 Permissions
118 of Health Connect's 219 framework permissions are symptom strings added at API level 37. Read vs write, medical, background and history, counted.
health-connectandroiddata
6 min read
The Fitness API Cost Your Users Pay
5 of 24 products bill your end user, not you. All five are direct wearable integrations, and the hardware requirement, not your budget, sets your reach.
wearablescostapi
Get the Fitness API Decision Kit — free
Sign up and the downloads appear instantly: the API selection checklist, the launch compliance checklist, the motion-SDK scorecard, and the full 2026 dataset. After that, one email when something actually changes — a deadline, a term, a deprecation. No fluff, no spam.
- ✓ API selection checklist
- ✓ Launch compliance checklist
- ✓ Motion-SDK scorecard (CSV)
- ✓ Fitness APIs 2026 dataset