AgTech APP for Farmer to handle the extreme weather to ensure the food production

Title: Full-Stack Development (Flutter/React Native + PostGIS) for Offline-First AgTech Mobile & Web App Category: Mobile Development, Web Development, GIS Software Development Budget / Type: Fixed Price / Milestone-Based (Target Budget: $60,000 – $95,000 across 5 Milestones) Project Description We are seeking an experienced full-stack development team or agency to build AgriPulse Brazil, a cross-platform mobile app (iOS & Android) and web admin portal for Brazilian farmers (produtores rurais). The platform optimizes farm operations by combining geospatial field mapping, localized climate analytics, expense/input tracking, an agronomic calendar, and a peer-to-peer farmer messaging network. Key Technical Requirements & Core Architecture Target Platforms: Mobile: Cross-platform iOS & Android (Flutter or React Native with clean architecture). Web: Admin & Management Dashboard (React / Vue / Angular). Offline-First Architecture (CRITICAL): Rural network coverage in Brazil is unreliable. The mobile app MUST support full offline data entry (cost tracking, field inputs, calendar events, polygon caching) and seamlessly perform bidirectional background sync once internet connectivity is restored. In your proposal, explicitly state your proposed offline sync framework (e.g., WatermelonDB, PowerSync, Realm). Geospatial & GIS Mapping: Interactive boundary drawing/editing for farm fields (talhões) using Mapbox or Google Maps API. PostgreSQL + PostGIS database for storing and processing GIS shapefiles, polygon coordinates, and spatial queries. Localization & Local Integrations: Language: Portuguese (Brazilian). Currency: Brazilian Real (BRL R$). Units: Hectares (ha), sacas/ha, kg/ha, L/ha. Payments: Subscription gateway supporting Pix (instant payments) and credit cards via Mercado Pago or Stripe Brazil. Compliance: Strict adherence to Brazil's LGPD (Lei Geral de Proteção de Dados). Key Modules: Auth & Multi-User Role Management (Owners, Managers, Field Hands). Live Map & Polygon Boundary Management. Agronomic Calendar & Local Weather Alerts (INMET / OpenWeather). Historical Climate Risk Analytics (INPE / Sentinel satellite datasets). Input, Cost & Resource Tracker (Custo por Hectare, ROI & PDF/Excel exports). P2P Farmer Community Messenger (WebSockets/Firebase, text, photos, voice notes). Tiered Subscription Engine (Fixed fee for 50 ha). Expected Deliverables & Project Phases We plan to structure the contract into 5 clear milestones: Milestone 1: UI/UX Design System (Figma), High-Fidelity Prototypes, and Technical Architecture Blueprint. Milestone 2: Core Backend & Offline-First Mobile Engine (User Auth, Offline DB Sync, GIS Map Boundaries). Milestone 3: Weather, Agronomic Calendar & ERP/Cost Tracking Modules. Milestone 4: P2P Community Chat, Payment Gateway (Pix + Cards), and Subscription Portal. Milestone 5: QA Testing (Offline Sync Stress Tests, LGPD Audit), App Store & Google Play Publishing, and Cloud Infrastructure Setup (AWS/GCP in São Paulo region). Screening Questions for Bidders Please answer the following questions when submitting your proposal: Offline Sync Experience: What specific sync engine or database architecture do you recommend for offline-first bidirectionally synced apps, and why? GIS Portfolio: Can you share 1–2 examples of mobile or web apps you’ve built that involve GIS mapping, polygon boundaries, or PostGIS? Brazilian Market Experience: Have you previously integrated Pix payment gateways (Mercado Pago / Stripe Brazil) or worked with LGPD compliance requirements? Team Structure: Who will be assigned to this project (e.g., Tech Lead, Mobile Developers, Backend Engineer, UI/UX Designer, QA)?