Senior React/Next.js Developer (TypeScript & Supabase) for Health/Wellness PWA (MVP)

Budget: $3,000 - $5,000 (Fixed Price) Timeline: MVP delivery by late August 2026 (Hard launch on Aug 30, 2026) Project Type: One-time project (with high potential for long-term maintenance and future React Native native app development) About the Project & Workflow We are building the MVP for Peaceflow (you can see our brand context and upcoming book release at peaceflow.me), a science-backed nervous system regulation and breathing app. The core of the app is the "Peaceflow Compass," a highly responsive interactive tool that guides users through breathing exercises and calculates their "Peace Score" (PS). My commitment as a client: This project is my absolute full-time focus. I work highly professionally. A clickable prototype already exists, meaning the concept is fully mature. You will not have to guess what I want. I will provide specific, detailed development tickets (User Stories & Acceptance Criteria). At the same time, I highly value your technical expertise and leave room for you to bring your best architectural ideas to the table. To shorten the application process, I have attached the full MVP Concept Document and a visual of the Compass. Please use this to give a realistic fixed-price quote. Design & Assets (The Compass) We need a highly complex, beautiful SVG vector for the Compass. If you are a rare "Unicorn" (Full-Stack Developer AND Top-Tier UI/SVG Designer), you can take on this design task as well. If your focus is purely on code, that is perfectly fine! I will hire a dedicated external designer to provide you with the clean, animated SVGs. Just let me know in your proposal. The Tech Stack (Non-Negotiable) To apply for this job, you must be highly proficient in the following stack: Frontend: React / Next.js (Strictly TypeScript) Backend & Auth: Supabase (PostgreSQL database) Payments: Stripe (Subscription logic) Architecture: PWA (Service Workers, IndexedDB for offline caching) Internationalization: i18n setup required (launching in German first de.json, but must be ready for English) Version Control: GitHub (Client will retain full ownership of the code from day one) Core Features (MVP Scope) The Interactive Compass (Main View): Click-anywhere mechanic to start/stop the compass needle. Precise calculation of a "Cooldown" timer based on the user's score. Hard-lock state during cooldown (UI becomes unclickable except for a cancel button). Audio triggers (Start, Stop, Cooldown End) optimized for strict iOS/Chrome autoplay policies. Dashboard, Gamification & Data Architecture (CRITICAL): Calculation of the long-term "Peace Score" (Average of today, 7 days, 30 days). Strict Event-Based Storage: The Supabase backend must store every single completed session as a new, unique row. We are collecting data for future scientific analysis. Averages must be calculated on the fly; historical raw data must never be overwritten. Gamification ("Flow Booster"): Implement unlock mechanisms (e.g., an animated Rocket icon that activates after 10 successful sessions, and text areas that unlock based on session counts). Freemium vs. Premium Logic (Paywall): Freemium: Basic compass design, limited text feedback, blurred historical stats with lock icons. Premium (via Stripe): 14-day free trial. Unlocks high-end compass design (UI asset swap), full historical data, and deep neuro-biological text feedback. Note: Data must be recorded for Freemium users in the backend so it unlocks retroactively upon upgrade. Navigation, Onboarding & Compliance: Hidden "Burger Menu" for secondary pages (Account/Stripe Portal, Medical Disclaimer, Legal/GDPR, Video Tutorial) to keep the main UI minimalist. Simple tutorial overlay on first login. Strict GDPR compliance on registration (Mandatory ToS checkbox + separate Optional Marketing checkbox). Why You Are the Right Fit You write clean, modular, and heavily typed TypeScript code. You have proven experience building PWAs that work flawlessly offline and sync data when back online. You know how to handle browser audio contexts to ensure sounds play correctly on iOS Safari. You understand relational databases and strict event-based logging. How to Apply Please include links to 1-2 PWAs or React applications you have built, ideally involving Supabase or complex state management (timers/audio). IMPORTANT: To ensure you have read this brief and understand the technical requirements, please start your proposal by answering this one question: How will you architect the audio triggers to ensure they don't get blocked by iOS Safari's strict autoplay policies when the user taps anywhere on the screen? We are looking for a reliable technical partner. If the MVP is successful, there is ongoing work for feature updates and native app development.