Full-Stack Mobile Developer Needed for MVP Location App (6-Week Core Build + 90-Day Retainer)

Job Title: Full-Stack Mobile Developer Needed for MVP Location App (6-Week Core Build + 90-Day Retainer) Job Description: We are seeking an expert, full-stack mobile application developer to build a lightweight, high-performance Minimum Viable Product (MVP) for iOS and Android tentatively titled Project BB. The app utilizes highly optimized background geofencing to log location events and deliver push notifications to a user’s local rewards wallet (The Vault). This is a fixed-price project broken down into strict, non-negotiable milestones with explicit time limits. Total core development must be completed in 6 weeks, followed by an active support retainer during a live 90-day pilot test. The app's primary purpose is to provide location attribution for local outdoor media displays. 🛡️ Mandatory Intellectual Property & Code Security Protocols To protect the integrity of our codebase, the selected developer must strictly adhere to the following architectural security measures from day one: - Repository Ownership: All development must occur inside a private GitHub repository owned exclusively by the client. Code must be committed and pushed daily. - No Hardcoded Secrets or Credentials: API keys, database URLs, and server credentials must never be committed to source control. All configurations must reside in secure environment variables (.env) utilizing a secrets manager. -Token-Based API Security: The connection between the app and the backend database must utilize secure, token-based authentication (OAuth2 / JSON Web Tokens). -No Proprietary/Black-Box Third-Party Libraries: The developer is strictly prohibited from using proprietary, obfuscated, or untrusted third-party SDKs that have not been vetted by the client. All packages must be open-source, widely supported, and inspectable. -Immediate IP Assignment: Acceptance of this Upwork contract constitutes a formal assignment of all intellectual property, source code, visual designs, and architectural logic directly to the client upon milestone payment. ⚙️ Core Technical Requirements - Cross-Platform Framework: Flutter or React Native preferred (Single codebase for iOS & Android). - Backend & Database: Light-weight framework (Node.js, Firebase, or Supabase) capable of reading geographic data rapidly. - Location Services: Highly efficient background GPS tracking using native OS geofencing APIs (designed to optimize and minimize user battery drain). - Push Notifications: Integration with Apple APNs and Google FCM (100% free app-native notifications; no SMS gateways). 📅 Project Milestones & Time Limits The budget is broken into a fixed-percentage milestone structure. You will only begin work on a milestone once Upwork escrow is fully funded. Each phase has a strict time limit: Milestone 1: Architecture, Database Blueprint & UI Layout - Budget Allocation: 15% - Time Limit: 1 Week (7 Calendar Days from contract start) - Deliverables: Database schema setup, configuration of the private GitHub repository, setup of secure .env framework, and functional front-end visual screen layouts for testing. Milestone 2: Core Background Geofencing Logic - Budget Allocation: 25% - Time Limit: 2 Weeks (14 Calendar Days from Milestone 1 approval) - Deliverables: Integration of background location tracking that successfully triggers a log when a user device enters specific designated GPS coordinates tied to our target outdoor media displays. Must run silently in the background and minimize battery depletion. Milestone 3: The Vault System & Automated Push Notifications - Budget Allocation: 25% - Time Limit: 2 Weeks (14 Calendar Days from Milestone 2 approval) - Deliverables: The digital user rewards wallet interface. Automated trigger mechanics that instantly send a push notification when an outdoor media display geofence is activated, moving the corresponding reward into the user’s active wallet with custom individual cooldown limits (e.g., 24-hour reset or monthly limits). Milestone 4A: Simple Admin Sheet & Beta Test Launch - Budget Allocation: 10% - Time Limit: 1 Week (7 Calendar Days from Milestone 3 approval) - Deliverables: Connecting the app's backend to a clean, manageable admin sheet interface allowing the client to easily create, modify, or update merchant rewards manually. Deployment of the live app build to Apple TestFlight and Google Play Beta Console. Milestone 4B: 90-Day Active Live-Support Retainer - Budget Allocation: 25% - Time Limit: 13 Weeks (90 Days continuous) - Deliverables: Ongoing technical support, on-call server monitoring, and immediate hot-fixes for any technical bugs discovered during our active 90-day regional pilot testing phase. 💬 How to Apply When submitting your proposal, please answer the following questions clearly: 1. What cross-platform framework (React Native or Flutter) do you recommend for optimized background location tracking, and why? 2. Can you explicitly commit to delivering the core application within the mandatory 6-week timeline under our daily GitHub check-in protocol? 3. Provide a brief example of a mobile app project you completed that involved geofencing or live map integration.