The idea
A fitness and wellness app helps users track workouts, follow exercise programs, monitor health metrics, and stay motivated. The model works through subscriptions — users pay monthly for access to premium content, personalized plans, or coaching features.
Founders build fitness apps because the market is massive and fragmented. While Peloton, Nike Training Club, and MyFitnessPal dominate general fitness, there are thriving niches in yoga, calisthenics, running, martial arts, senior fitness, prenatal wellness, and physical therapy. Each niche has dedicated users willing to pay $10–$30/month for the right tool.
The biggest challenge isn't building the app — it's retention. Fitness app average 30-day retention is around 20%. The apps that succeed do so by creating habits: streaks, progress tracking, social accountability, and content that evolves with the user.
Tech stack we'd use
Core features (MVP scope)
- Workout library: Categorized exercise library with instructions, images or video demos, difficulty levels, and target muscle groups. Content is the product — this needs to be excellent.
- Workout tracking: Log workouts with sets, reps, weight, and duration. Timer functionality for timed exercises. Automatic tracking through HealthKit/Google Fit for cardio activities.
- Progress dashboard: Visual progress tracking with charts — workout frequency, volume over time, personal records, streaks, and body metrics (weight, measurements) if the user opts in.
- Workout plans and programs: Pre-built multi-week programs that guide users through a structured progression. Each day has a prescribed workout with exercises, sets, and rest periods.
- HealthKit and Google Fit sync: Two-way sync with device health platforms. Import steps, heart rate, and activity data. Export workout data so it appears in the user's Health app.
- Push notification reminders: Scheduled workout reminders, streak alerts (don't break your streak!), and achievement notifications. Push notifications are the primary retention mechanism.
- Subscription management: Free tier with limited content, premium tier with full access. In-app purchase flow via RevenueCat, with free trial option and annual discount.
- User profiles: Basic profile with fitness goals, experience level, and preferences. Used to recommend appropriate workout programs and track overall progress.
What we'd cut from v1
- Social features and community: Leaderboards, friend challenges, and in-app communities are powerful for retention but require moderation, content policies, and significant UX work. Add social after core workout tracking is solid.
- AI-generated workout plans: Personalized AI plans based on user history and goals are a compelling feature but require significant ML work and training data you don't have yet. Use curated programs first.
- Live streaming classes: Live classes require video infrastructure (low-latency streaming, chat), scheduling, and instructor management. This is a separate product vertical — add it when you have an audience.
- Nutrition tracking: Food logging with calorie and macro tracking is essentially a second app. Integrate with MyFitnessPal's API if users want this rather than building from scratch.
Cost breakdown
| Phase | What's Included | Cost Range | Timeline |
|---|---|---|---|
| Discovery & Design | User research, app UX design, workout UI patterns, progress visualization design | $3,500–$7,000 | 2 weeks |
| Frontend Development | React Native app (iOS + Android), workout player, progress charts, profile screens | $6,000–$14,000 | 3–5 weeks |
| Backend Development | Firebase setup, HealthKit/Google Fit integration, subscription management, content CMS | $6,000–$16,000 | 3–5 weeks |
| Testing & Launch | Device testing, HealthKit validation, App Store submission, Google Play submission | $2,500–$5,000 | 1–2 weeks |
| Post-launch Support | Bug fixes, content updates, retention optimization (30 days) | $2,000–$3,000 | Ongoing |
The build timeline
Weeks 1–2: Discovery and design. We define the fitness niche, research competitor apps, and design the core UX — workout player, progress dashboard, and program browsing. Fitness app design is highly visual and needs to motivate, not just inform.
Weeks 3–6: Core app development. React Native app with workout library, tracking functionality, and progress dashboard. Firebase backend with authentication, database, and cloud storage. HealthKit and Google Fit integration. This phase is the heaviest — health platform APIs have strict requirements and device-specific quirks.
Weeks 7–10: Content, subscriptions, and notifications. Workout program content entry, RevenueCat subscription integration (with free trial flow), push notification system for reminders and streaks. We also build the basic content management system for adding new workouts and programs.
Weeks 11–14: Testing and App Store submission. Testing on multiple devices (different iPhone models, various Android devices), HealthKit permission flow testing, subscription flow testing, and App Store/Google Play submission. Apple's review process typically takes 1–3 days but can require revisions.
Why this approach
We use React Native over native Swift/Kotlin because the fitness app's core features (workout tracking, progress charts, content browsing) don't require native-only APIs. HealthKit and Google Fit have well-maintained React Native bridges. Building native for both platforms would nearly double the cost and timeline.
Firebase over a custom backend because fitness apps have predictable data patterns (user profiles, workout logs, progress metrics) that fit Firebase's document model well. Real-time sync means workout data appears instantly across devices, and Firebase's offline support means users can log workouts without internet.
RevenueCat is essential for mobile app subscriptions. Managing App Store and Google Play subscriptions directly is a known pain point — receipt validation, subscription status tracking, grace periods, and refund handling are all complex. RevenueCat abstracts this for $0 (up to $2.5K MTR) and saves 2–3 weeks of development.
The $20K–$45K range reflects the mobile-first nature of this build. The low end covers a focused fitness niche with curated content and basic tracking. The high end adds custom workout plan generation, advanced progress analytics, and more polished UI animations.
Frequently asked questions
A fitness app MVP costs $20,000–$45,000, covering iOS and Android apps with workout tracking, progress visualization, HealthKit/Google Fit integration, and subscription billing. Advanced features like AI-powered plans, live streaming, or social features can push costs to $80,000–$200,000+.
A fitness app MVP takes 10–14 weeks. The timeline includes 2 weeks for design, 8–10 weeks for development (including HealthKit/Google Fit integration and subscription management), and 1–2 weeks for testing and App Store submission.
Basic fitness apps can be built with tools like Glide or Adalo, but they can't integrate with HealthKit/Google Fit, handle in-app subscriptions properly, or deliver the smooth native experience users expect from fitness apps. For content-only apps (video libraries), no-code can work. For tracking and wearable integration, custom development is necessary.