Flutter Developer for App Creation

Flutter Frontend Developer — Clinical Health Platform (Web + iOS/Android) About This Project We are building a clinical intelligence platform for a women's metabolic health practice. The backend is fully operational — Firebase, Python, and Go microservices are live and maintained by a dedicated backend developer. We need an experienced Flutter developer to own the frontend entirely: translating finalized UI/UX mockups into a production-grade, responsive application and integrating it with the existing backend services. This is not a prototype. This is a production build for a live clinical practice opening August 2026. What You Will Build A cross-platform Flutter application serving two audiences: Patients — Mobile-first experience for connecting wearable devices, viewing health data, managing appointments, and receiving provider communications. Clinical Staff / Providers — Web-optimized dashboard for reviewing patient data, clinical scoring output, and workflow management. The backend developer will handle all server-side work. Your scope is the Flutter client and its integrations only. Platform Priority (Non-Negotiable) You will maintain a single Flutter codebase structured for adaptive, responsive layouts across: Primary: Web — optimized for desktop and mobile browsers Secondary: iOS and Android native apps Tertiary (future-proof): iPadOS and macOS — UI architecture must scale without redesign Scope of Work 1. Codebase & Design Evaluation Review provided UI/UX design mockups and existing beta Flutter codebase. Determine whether to build from the current foundation or start fresh. Document your decision with rationale before writing a line of production code. 2. UI/UX Implementation Convert design mockups into pixel-perfect, responsive Flutter screens. Web views must support both touch and keyboard/mouse paradigms. Mobile views must feel native, not ported. 3. Firebase Integration Connect the Flutter frontend to the live Firebase backend using official FlutterFire packages: Authentication: Auth state management, sign-up/login flows, session handling Data & Storage: Firestore real-time sync, Firebase Storage Service Calls: Triggering Python/Go microservices via Firebase endpoints Real-time data streams must be handled without unnecessary re-renders 4. Open Wearables Flutter SDK Integration (Required — Read Carefully) This is a non-negotiable scope item. The platform integrates with Open Wearables — a self-hosted, open-source wearable data platform — to ingest patient health data from Apple Health, Oura, Garmin, Whoop, and other providers. Your responsibilities: Implement the Open Wearables Flutter SDK (open_wearables_health_sdk) within the iOS and Android native builds Build the patient-facing wearable connection UI using the Open Wearables OAuth connection widget, allowing patients to authorize their wearable providers from within the app Configure Apple Health / HealthKit integration including: HealthKit permission request flows Background delivery and incremental data sync iOS Keychain token storage and session restoration Background app refresh entitlements Implement SDK authentication handshake with the self-hosted Open Wearables backend (maintained by backend developer) Route synced wearable data payloads to Firebase for CIS ingestion via webhook-compatible data flow Critical context: Apple Health has no backend API. HealthKit only operates on a physical iOS device through an on-device SDK. The Flutter SDK is the only path to Apple Health data. This is not optional and cannot be delegated to the backend. The backend developer handles Open Wearables server deployment and configuration. You handle the Flutter SDK integration on the client side only. 5. State Management Implement clean, performant state management for real-time Firebase streams. No unnecessary rebuilds, no blocking UI on async calls. Architecture must be maintainable by another developer after handoff. 6. Cross-Platform Testing Test and validate on: Chrome and Safari (desktop and mobile web) Physical iOS device (required for HealthKit validation — simulator will not suffice) Physical Android device Tablet viewports (iPadOS scaling) Technical Requirements You must demonstrate proven, shipped experience in each of the following. Candidates who cannot provide evidence will not be considered. Required: Flutter and Dart — advanced proficiency, production apps shipped Flutter Web — deep understanding of web rendering (DOM vs. WASM), declarative routing, URL/back-button handling, responsive breakpoints, web asset optimization FlutterFire — hands-on experience with Firestore, Firebase Auth, Firebase Storage, real-time data streams Apple HealthKit — shipped iOS app using HealthKit, background delivery, and permission flows Open Wearables Flutter SDK or equivalent health SDK experience (HealthKit wrappers, background sync, on-device auth) Adaptive/responsive layout architecture — LayoutBuilder, MediaQuery, responsive grid systems Clean architecture principles, clear documentation, Git version control Strong Preference: Experience building for regulated environments (HIPAA, clinical, health data) Familiarity with OAuth flows in mobile apps Experience with webhook-based data routing in Flutter Out of Scope The following are explicitly excluded from this engagement: Backend development, schema changes, or modification of Python/Go microservices Server-side Firebase configuration or infrastructure management Deployment or maintenance of the Open Wearables backend instance (FastAPI/PostgreSQL/Redis/Celery) — owned by backend developer UI/UX design — mockups will be provided; you implement, you do not design Deliverables & Milestones Milestone Deliverable M1 — Setup & Architecture Codebase audit documentation, architecture decision record, environment initialization, Firebase Auth flows functional, state management pattern established M2 — Web UI & Firebase Integration All core screens rendered and responsive for desktop and mobile web; fully integrated with live Firebase endpoints; real-time data streams operational M3 — iOS/Android + Wearable Integration Native mobile builds complete; Open Wearables Flutter SDK integrated; Apple Health HealthKit permission flows, background sync, and Keychain auth operational; wearable OAuth connection UI complete; validated on physical iOS and Android devices M4 — Testing, Polish & Handoff Bug fixes; performance profiling (web load times, HealthKit sync reliability); tablet/desktop scaling validated; clean code delivery with documentation; final deployment builds How to Apply Your proposal will be disqualified without the following: Links to at least two published Flutter apps currently live in the App Store, Google Play, or as deployed web applications. At least one project must include Apple HealthKit integration. Link to the app and, if available, the source repository. A brief technical response (3–5 sentences) explaining how you have handled Apple Health background sync in a prior project — specifically how you managed background delivery entitlements and HealthKit permission states across iOS versions. Your assessment of the Open Wearables Flutter SDK — have you used it, or are you familiar with it? If not, confirm you have reviewed the documentation at openwearables.io/docs/sdk/flutter and describe how you would approach the integration. Your estimated timeline broken down by milestone. Generic proposals will not be reviewed. We are looking for a developer who has done this work before, not one who will learn it on our project. Engagement Details Type: Contract / Project-based Compensation: Fixed-price per milestone, negotiated based on experience and proposal Communication: Async preferred; availability for scheduled milestone reviews required Code Delivery: Private GitHub repository; clean commits, documented architecture This is a clinical environment handling protected health information. The selected developer will be expected to operate with discretion and professionalism consistent with a healthcare context.