Senior Mobile App Developer / Full-Stack Team — Build FitAdapt AI

Project Overview We are looking for an experienced mobile app developer or small development team to build FitAdapt AI, a personalized fitness application for iOS and Android. FitAdapt AI is designed around one core idea: «Your workout changes with you.» Instead of giving every user the same workout plan, the application will use a user's profile, goals, fitness level, recent workout history, and daily readiness to dynamically recommend an appropriate Light, Moderate, or Heavy workout. We already have the initial product concept and UI direction and are looking for a developer/team capable of turning the concept into a polished, scalable MVP. Core Features 1. User Registration & Profile Users should be able to create an account and enter: - Age - Sex - Height - Weight - Fitness level - Workout experience - Primary fitness goal - Available equipment - Days per week - Preferred workout duration - Fitness preferences - User-reported limitations relevant to exercise 2. Daily Readiness Check Before a workout, users provide simple feedback: - Energy level: 1–10 - Muscle soreness: 1–10 - Sleep quality: 1–10 - Stress: 1–10 - Previous workout difficulty: 1–10 The application will calculate a readiness score and use it as one input into the workout recommendation. 3. Adaptive Workout Engine The core feature of the application. The system should determine an appropriate workout intensity: - 🟢 Light - 🟡 Moderate - 🔴 Heavy The workout recommendation should consider: - User profile - Fitness level - Goal - Recent workouts - Workout performance - Readiness - Previous difficulty ratings - Available equipment - Workout duration - Training frequency The system should progressively adjust workouts based on user feedback and performance. Important: We want the core exercise/intensity rules to be controlled by application logic rather than allowing an LLM to independently make potentially unsafe exercise decisions. 4. Workout Player Each workout should provide: - Exercise name - Exercise instructions - Reps/time - Sets - Rest timer - Exercise demonstration/video support - Previous/next exercise - Pause/resume - Workout progress - Exercise substitutions where appropriate At the end of the workout: «How difficult was this workout?» Users can rate the workout from 1–10 and select: - Too Easy - Good - Too Hard This feedback should influence future recommendations. 5. Progress Tracking Users should be able to view: - Weight history - Workout history - Workout frequency - Workout streak - Fitness score - Workout duration - Training progress - Personal records where applicable Include attractive charts and a clean mobile interface. 6. AI Fitness Coach Add an AI-powered conversational coach. Example user requests: «"I only have 20 minutes today."» «"I don't have any equipment."» «"Make today's workout easier."» «"I missed yesterday's workout."» The AI should respond using the user's available profile/workout information and work within the application's predefined safety and workout rules. The AI should not diagnose medical conditions or provide medical treatment. 7. Safety System The application should include safeguards around exercise recommendations. If a user reports concerning symptoms or significant pain, the application should avoid generating an aggressive workout and provide appropriate safety guidance. We want this implemented as application-level rules rather than relying entirely on AI. 8. Admin Dashboard We would like an admin interface for managing: - Users - Exercises - Exercise categories - Workout templates - Workout levels - Workout rules - Content - AI configuration - Basic analytics The architecture should allow us to add and modify exercises and workout templates without releasing a new version of the mobile app. Preferred Technology We are open to recommendations, but our preferred approach is: Mobile: Flutter or React Native Backend: Firebase or Supabase Database: PostgreSQL / Firestore or an appropriate scalable alternative AI: OpenAI API or another appropriate LLM API Authentication: Secure email/social authentication Payments: Apple App Store / Google Play subscriptions The developer should recommend the best architecture before development begins. Design Requirements We want a modern, premium fitness-app appearance. The design should be: - Dark/light mode capable - Clean - Modern - Fast - Easy to navigate - Mobile-first - Professional enough for a commercial App Store launch Initial screens include: 1. Welcome 2. Registration/Login 3. Profile setup 4. Goal selection 5. Readiness check 6. Home 7. Today's workout 8. Workout player 9. Workout completion 10. Progress 11. AI Coach 12. Profile/settings We have an initial visual concept/mockup available for reference. MVP Deliverables The successful developer/team will deliver: - iOS application - Android application - Backend - Database - Authentication - Adaptive workout engine - Exercise library - Workout player - Readiness system - Progress tracking - AI Coach integration - Admin dashboard - Subscription infrastructure - Analytics - Push notification support - App Store submission support - Google Play submission support - Production deployment - Complete source code Ownership All project deliverables must belong to the client. The developer must provide: - Complete source code - Database - Backend code/configuration - UI/UX files - API configuration - Documentation - Deployment instructions All accounts and infrastructure should ultimately be controlled by the client. We will not accept a solution where the developer retains exclusive control of the source code or production infrastructure. Development Process We prefer milestone-based development. Milestone 1 — Architecture & UI/UX - Finalize technical architecture - Finalize database structure - Finalize user flows - Finalize UI/UX Milestone 2 — Authentication & Profile - Registration/login - User profile - Goals - Fitness information - Equipment/preferences Milestone 3 — Workout Engine - Exercise database - Workout generation - Light/Moderate/Heavy logic - Readiness scoring - Adaptive progression Milestone 4 — Workout Experience - Workout player - Timers - Exercise instructions - Feedback - Workout completion Milestone 5 — Progress & AI - Progress dashboard - Charts - Workout history - AI Coach - AI integration Milestone 6 — Testing & Launch - QA - Bug fixing - Performance testing - Security review - App Store submission - Google Play submission - Production deployment Ideal Candidate We are looking for someone with proven experience in: - Flutter or React Native - iOS and Android development - Backend development - Firebase/Supabase - Database architecture - REST APIs - AI/LLM API integration - Subscription/payment integration - Modern mobile UI/UX - Fitness/health applications Experience building fitness, wellness, healthcare, sports, or AI-powered apps is strongly preferred. Please Include With Your Proposal 1. 3–5 examples of mobile applications you have personally built. 2. Links to App Store / Google Play applications if available. 3. Your recommended technology stack and why. 4. Your estimated development timeline for the MVP. 5. Your estimated total cost. 6. Your availability per week. 7. Who will actually work on the project. 8. Examples of AI integrations you have built. 9. Examples of subscription/payment integrations. 10. Explain how you would design the adaptive workout engine. 11. Explain how you would prevent the AI from making unsafe workout recommendations. 12. Confirm that all source code and intellectual property will be transferred to the client. Proposal Instructions To make sure you have carefully read this posting, please begin your proposal with: "FITADAPT" Then briefly explain how you would approach building the MVP. We are interested in building a long-term product, not simply completing a one-time coding project. Developers/teams who can help us evolve the product after launch are preferred. Budget We are open to proposals from qualified developers and teams. Please provide a fixed-price MVP proposal broken down by milestones, rather than only an hourly rate. We will select based on: - Quality - Relevant experience - Technical approach - Portfolio - Communication - Timeline - Price - Long-term support capability Please do not submit a generic AI-generated proposal. We want to understand your actual experience and how you would approach FitAdapt AI.