Fitness App Boilerplate for iOS
A HealthKit-friendly SwiftUI base wired for subscriptions, so you can spend your time on the workout logic instead of the auth screens, paywall plumbing, and account sync every fitness product needs before day one.
The Swift Kit is a fitness app boilerplate for iOS that costs $99 one-time and gives you a HealthKit-ready SwiftUI base plus a working RevenueCat subscription layer. It ships the parts every fitness product needs but nobody wants to rebuild — Sign in with Apple, a Supabase backend for syncing workout data across devices, and a tiered paywall for monthly, annual, and lifetime plans. You add the actual training, tracking, or coaching features; the account and billing foundation is already done.
Why fitness apps need a subscription-ready base, not just a UI kit
Almost every fitness app that makes money is a subscription business. A free workout logger does not pay your bills; a $9.99/month coaching plan or a $59.99/year training program does. That means the hard, boring 30% of a fitness app — the part that gates premium workouts behind a paywall, restores purchases when a user reinstalls, and tracks who is and is not entitled — has to exist before your first paying customer. The Swift Kit ships that layer with RevenueCat already wired: a configurable paywall, monthly/annual/lifetime tiers, and entitlement checks you can hang a 'Pro' workout library on. You write the fitness; the billing is solved on the day you clone the repo.
The HealthKit-friendly part — what's done and what's honestly on you
This is a fitness boilerplate, so let's be precise about HealthKit. The Swift Kit gives you a clean SwiftUI architecture that is friendly to a HealthKit integration — a centralized data layer, per-screen view models, and a Supabase sync path for the metrics you want stored server-side rather than only in Apple Health. What it does not do is ship a pre-filled HealthKit entitlement or pretend to read your users' step counts out of the box. HealthKit access requires your own capability, your own permission strings, and Apple review justification specific to your app. The kit removes the scaffolding around that work; the HealthKit request itself is yours to add.
- Centralized DesignSystem.swift so workout cards, rings, and stats retheme from one file
- Supabase Postgres for syncing logged sessions, streaks, and goals across a user's devices
- Sign in with Apple plus email auth, so health data ties to a real account from launch
- A clean place to drop your HKHealthStore reads/writes without fighting the architecture
What you build on top
The Swift Kit is deliberately not a finished fitness app — there's no opinionated workout engine, no exercise database, no rep counter. That is the point. Your differentiation is the training methodology, the coaching tone, the exercise library, or the recovery science, and a boilerplate that shipped all of that would force you into someone else's product. Instead you get the surrounding machinery: onboarding (3 styles, ideal for a goal-setting or fitness-level survey), push notifications for workout reminders and streak nudges, TelemetryDeck analytics to see which programs retain, and optional on-device AI via Apple Foundation Models for things like a free-tier form-feedback or plan-summary feature that costs you nothing per call.
- 3 onboarding styles — drop your fitness-goal questionnaire into a proven flow
- Push notifications for workout reminders, streak saves, and re-engagement
- TelemetryDeck analytics to measure program completion and retention
- Optional AI (OpenAI, Claude, free on-device Apple Foundation Models) for coaching-style features
When you should NOT use this — and a more honest alternative
If your fitness product lives or dies on deep HealthKit and Apple Watch integration — a real-time heart-rate workout app, a WatchOS-first companion, a HealthKit-data-science product — then a generic boilerplate buys you less. The auth and paywall are still useful, but the bulk of your engineering is in HealthKit and watchOS code this kit does not provide, and you may be better served building that core from scratch and bolting on a payment library directly. Likewise, if you genuinely don't plan to charge — a free, ad-free passion project — paying $99 for a subscription-first kit is the wrong tool. The Swift Kit is at its best when you are building a subscription fitness app that needs accounts, sync, and a paywall fast, and treats HealthKit as one feature among many rather than the whole product.
Swift Kit vs building your fitness app from scratch
| Feature | The Swift Kit ($99) | Build from scratch |
|---|---|---|
| Subscription paywall + tiers | RevenueCat wired, monthly/annual/lifetime | Integrate StoreKit/RevenueCat yourself (days–weeks) |
| Auth + account for health data | Sign in with Apple + email, day one | Build and test from zero |
| Cross-device workout sync | Supabase Postgres included | Stand up and secure your own backend |
| HealthKit integration | Friendly base, you add the entitlement | You add the entitlement (same work) |
| Design system / retheme | One-file DesignSystem.swift | Hand-roll styling per screen |
| Time to first paying user | Days | Weeks to months |
| Cost | $99 one-time, lifetime updates | Your time (the expensive part) |
Frequently Asked Questions
Does the Swift Kit include a working HealthKit integration?
How are fitness subscriptions handled?
Where is workout and progress data stored?
Can I build a free-tier AI coaching feature without per-call costs?
Is this a good fit for a watchOS-first or heart-rate-focused fitness app?
What does it cost and are there ongoing fees?
Keep exploring
Ship your fitness subscription app, not its plumbing
Start from a HealthKit-friendly SwiftUI base with RevenueCat subscriptions, Supabase sync, and Sign in with Apple already wired. $99 one-time, lifetime updates, 14-day refund — so you can spend launch week on workouts, not auth screens.
Get The Swift Kit — $99One-time purchase · Lifetime updates · 14-day refund