Apple Watch vs Garmin: Which Should You Build On?

Two gates, and only one of them is yours to clear#

Both of these strap a sensor to a wrist, and both charge the wearer once, up front, with nothing recurring required for the data to exist. Almost none of the engineering decision follows from that. It follows from a different split: a platform you build on versus a partner API you apply for.

Building on Apple Watch means you never call Apple. Apple documents HealthKit as "a central repository for health and fitness data on iPhone and Apple Watch," and its privacy guidance says plainly that "the user's device stores all HealthKit data locally" and that "the device encrypts the HealthKit store when the user locks the device." There is no endpoint, no client credential to rotate, and no vendor quota to negotiate, because Apple runs no server on its side of this relationship. Your code runs on the user's own hardware inside an app you ship. What you inherit in place of an API contract is Apple's platform rulebook: the HealthKit capability, the NSHealthShareUsageDescription and NSHealthUpdateUsageDescription strings (call the authorization API without the matching key and the app crashes instead of showing a sheet), App Review before anyone can install the thing, and a permission prompt whose read outcome you cannot inspect.

Garmin inverts all of it. The Connect Developer Program is partner-approval-only: you apply, and Garmin's team must approve a partnership before you receive any credentials. There is no self-serve key and there never was. Once you are in, current docs specify OAuth 2.0 with PKCE producing a per-user userAccessToken, and you do not poll — you register HTTPS callback URLs per summary type and Garmin POSTs when a user's device syncs, either as a Ping notification carrying a callbackURL you then GET with that user's token, or as a Push with the full JSON inline. Good server-side architecture; the trouble sits upstream of it. As of 2026 new sign-ups are reportedly on hold, the public access-request form appears to have been removed, community and issue-tracker reports describe the program as "on hold" for new applicants for several months, and there is no published re-open ETA. Existing approved partners are said to be unaffected.

Neither posture is a knock on either company, but they hand you different problems. Apple's gate is on distribution, and you can always clear it eventually; Garmin's gate is on access, and right now you may not be able to clear it at all.

Apple Watch vs Garmin at a glance#

No Garmin price appears above because none is confirmed: there is no evidence of a published per-request fee, and no confirmation the program is free either. Commercial terms are settled privately with approved partners.

Where Apple Watch wins#

There is no counterparty who can say no. This is the whole argument, and it lands unusually hard against Garmin. You cannot be paused out of HealthKit: if the person owns the watch and taps allow, the samples are there today — no application, no queue, no partner agreement whose terms you cannot read in advance.

You can run code on the device mid-workout. Shipping a watchOS app and driving HKWorkoutSession is something a push-callback API structurally cannot offer: Apple documents the session as one that "fine-tunes Apple Watch's sensors for the specified activity" and notes that "all workout sessions generate high-frequency heart rate samples." Live coaching, real-time pace or form feedback, and haptics on the wrist live here, not in a summary that arrives after the device next syncs.

You get the whole store — including, sometimes, Garmin's data. Because HealthKit is a shared repository, your app sees what other apps and devices wrote into it. The consequence for this pair is specific: if a user's Garmin data lands in Apple HealthKit, you can read it on-device without Garmin's API at all. Not a substitute — you get only what synced into that one user's store, on the phone — but a real reason these two are not strictly exclusive.

The honest trade-off. You are signing up to build and ship an app, forever, on iOS and watchOS only. Background reads can fail while the device is locked, because the store is encrypted then. Your app cannot tell "granted" from "denied" on reads, so your empty state must work without knowing why it is empty. Background delivery is metered by the system. And the sync to your servers is entirely your code — the HealthKit integration guide covers the permissions, queries and sync you will write.

Where Garmin wins#

Breadth of first-party physiology. The Health and Activity API split reaches further into all-day wellness and serious multisport than most wearable APIs: Body Battery, VO2 max, stress, respiration, per-minute epochs, and 100-plus sport types with GPS and session detail. On the Apple side you get whatever that individual's devices and apps happened to write.

Your backend receives data without the user present. A web dashboard with no mobile app, a nightly cohort job, an Android-first product — none are buildable on Apple Watch data alone, and all are ordinary Garmin integrations. Push carries the full payload inline; Ping keeps the POST small and lets you control fetch timing. And nobody has to keep your app installed: with HealthKit your app is the pipeline, so uninstalled or unpermitted, it stops.

The honest trade-off. All of it is downstream of approval, and approval is the whole game. Nothing here is a stable public contract either: hosts, paths, scopes, summary-type names and token lifetimes sit behind the partner docs and change, so do not hard-code values from any public write-up, this one included. If the gate rather than the data is your blocker, can't get Garmin API access covers the live status check and the aggregator route that runs on somebody else's approved credentials; the Garmin API integration guide covers the wiring once you are in.

How to choose#

• An iOS or watchOS app, especially one that coaches during the set → Apple Watch. Nothing in a callback API reaches the sensors mid-session.
• A web product, an Android app, or a backend that runs without the user present → Garmin, if you can get in. Confirm program status before you plan a roadmap around it.
• You want to start this week → Apple Watch. Garmin's review runs to weeks when the form is open, and reportedly cannot be submitted at all right now.
• The deepest first-party physiology on an owned device → Garmin, with the metric list verified against the partner docs.
• Your users must not pay a subscription → both qualify, which is unusual. This pair ties on user cost; if that axis is what you are weighing, the contrast lives in Apple Watch vs WHOOP, where one side is a membership.
• You are really asking cloud-versus-device in general → Fitbit vs Apple Watch walks that split with a self-serve cloud vendor opposite, which is a different question from an approval queue.

Watch the fine print#

The Apple specifics are documented behaviour and move slowly, but confirm the current background-delivery frequencies, entitlement requirements, platform availability and type identifiers in Apple's own HealthKit documentation. The Garmin specifics are the volatile half, and several are second-hand by necessity: the docs are gated, and most primary pages return errors to anonymous fetches. The reported sign-up pause, the roughly three-month token lifetime, the summary-type names, the metric lists, and any setup fee or premium-metric licensing are all unconfirmed on a Garmin-owned page. Load the developer portal yourself before telling a stakeholder the program is closed. Everything above is as of 2026 — verify.