# Fitness and motion app development: workouts, camera rep counting and game mechanics by ODEL > Building a fitness, warm-up or movement app: workouts, on-device camera tracking, multiplayer and purchases, when Trainerize or a gym platform fits better, and what ODEL learned from Warmify. ODEL builds fitness and movement apps: workout and warm-up routines, timers, camera-based rep counting and form checks that run on the device, XP and game mechanics, head-to-head play and in-app purchases. ODEL designed, built and publishes Warmify, a warm-up workout game for iPhone and Android in which the phone camera counts reps and checks form 30 times a second without uploading frames, with 8 sport modes, Duo on the TV and online Versus matches. Personal trainers and gyms that mainly need client programs, scheduling and payments are usually better served by an existing platform such as Trainerize or their gym software's branded app. A custom app fits a new workout product, a sport-specific program or a movement game. Projects start with a discovery call and a written scope, and the app ships under your developer account with the source code yours. ## Who it is for - Founders building a workout, warm-up, stretching or movement product - Coaches and sports organizations with a specific program they want in an app - Teams that want camera-based motion tracking or game mechanics in a fitness app - Owners of an existing fitness app that needs new features, Android or a paywall rebuild ## When ODEL is not the right fit - Personal trainers who need client programs, messaging and payments: Trainerize or TrueCoach do this today - Gyms and studios that need class booking and memberships: use your gym management software's branded app - Apps that make medical or rehabilitation claims ## What you get - Routine and program screens with timers - On-device camera motion tracking for reps and form, with no video upload - XP, streaks and progress - Local or online multiplayer modes - Optional Apple Health workout logging - Subscriptions or one-time cosmetic packs - Camera permission priming and privacy answers - Store listing, screenshots and preview video ## How the project runs 1. **Build or buy check**: Trainer and gym needs usually fit existing platforms; we say so up front. 2. **Movement spec**: Which exercises, how a rep is counted, what counts as good form and what the app says when it cannot tell. 3. **Prototype the hard part**: Camera tracking or the core loop is built first and tested on real devices. 4. **Build the product around it**: Programs, progress, purchases and modes in milestone builds on your phone. 5. **Launch**: Store setup, privacy answers and review under your account. 6. **After launch**: New modes, device testing for new phones, ASO and pricing work. ## Technology Swift and SwiftUI, React Native and Expo, On-device camera pose tracking, HealthKit (optional), StoreKit and Google Play Billing, Node.js and PostgreSQL for accounts and matchmaking ## Apps ODEL built and runs - [Warmify](https://www.odel.dev/app/warmify.md): Warmify is a warm-up workout game where your phone camera counts reps and checks your form. ## Questions ### Should I build my own fitness app or use Trainerize? If you are a trainer selling programs and coaching, an existing coaching platform gets you running faster and cheaper. Build when the app itself is the product: a new way to train, a sport-specific program, camera tracking or a game. ### How much does it cost to build this kind of app? It depends on the number of exercises and modes, camera tracking, multiplayer or accounts, video content, Apple Health integration, and iPhone only or both stores. ODEL quotes each project after a short discovery call, as a written scope with a fixed quote or a phased plan, and publishes no price list. For market context only: Clutch's 2026 pricing guide puts the most common app project budget at 10,000 to 49,999 USD (Clutch does not state its sample size), and a 2022 GoodFirms survey of 267 development firms put simple apps at 12,960 to 30,240 USD. Store costs come on top: Apple charges 99 USD a year and Google Play 25 USD once. ### How long does it take to launch? It depends on scope, how fast decisions get made and whether your store accounts are ready. The 2022 GoodFirms survey put simple apps at 3 to 7 weeks and complex ones at 8 to 14 weeks of development. Then add store time: Apple says it reviews 90% of submissions in under 48 hours, and new personal Google Play accounts must run a 14-day closed test with at least 12 testers before production. Camera tracking needs testing on several real phones, which adds time compared with a timer-and-video app. ### Can the camera count reps without sending video anywhere? Yes. Warmify tracks the body on the device and checks form 30 times a second, and frames are never uploaded or stored. Keeping it on device keeps the privacy answers simple and works without a connection. ### What App Store rules matter for fitness apps? Guideline 5.1.3 limits how health and fitness data can be used and bars using it for advertising. Guideline 1.4 covers apps that could cause physical harm, and camera access needs a clear purpose string under 5.1.1. Subscriptions must state what the user gets for the price (3.1.2). ### What did ODEL learn building Warmify? A short routine with a clear goal is easier to start than a long workout, so Warmify is built around a 3-minute warm-up. XP for every rep, Duo on the TV and Versus online give people a reason to come back, and Warmify sells cosmetic packs and frames as in-app purchases rather than a subscription. ## Sources - https://clutch.co/directory/mobile-application-developers/pricing - https://prnewswire.com/news-releases/develop-a-simple-mobile-app-in-3-weeks-costing-just-12k-says-goodfirms-2022-survey-301542663.html - https://developer.apple.com/distribute/app-review/ - https://support.google.com/googleplay/android-developer/answer/14151465?hl=en - https://developer.apple.com/programs/enroll/ - https://support.google.com/googleplay/android-developer/answer/6112435?hl=en - https://developer.apple.com/app-store/review/guidelines/ - https://developer.apple.com/app-store/subscriptions/ - https://www.trainerize.com/ - https://truecoach.co/ Start a project: https://www.odel.dev/services#start (form) or info@odel.dev. ODEL quotes each project after a short discovery call; it does not publish fixed prices. Page: https://www.odel.dev/services/industries/fitness-and-motion-apps