An offline-first fintech platform for farmers in Kyenjojo, Uganda — with Firebase backend, NASA POWER climate API, GPS farm verification, Shoelace acreage calculation, and multi-language support (Runyoro/Luganda). Built by DeryCode.
The SACCO Digital Wallet is a mobile-first fintech platform designed for farmers in Kyenjojo, Uganda. It enables farmers to register, verify their farms via GPS, access savings and loan services, and get climate intelligence data to improve agricultural decision-making.
The platform was migrated from Supabase to Firebase for its backend, using Firestore for data storage and Firebase Auth for user management. The offline-first design ensures farmers in areas with poor connectivity can still access core features.
Key Features
Offline-first architecture optimized for low-end Android devices
Firebase Authentication and Firestore database
GPS-based farm boundary mapping and verification
Shoelace formula geometric acreage calculation
NASA POWER API integration for climate and weather data
Agricultural Intelligence module for crop recommendations
Multi-language support (Runyoro, Luganda, English)
Admin audit module with vendor verification and financial risk scoring
Automated PostgreSQL triggers for user registration lifecycle (profiles, wallets, farm_records)
Wallet and savings management with loan tracking
Technology Stack
React (Vite)Firebase AuthFirestoreNASA POWER APIGeolocation APIVercelShoelace AlgorithmPWA
The Challenge
Farmers in rural Uganda needed a financial tool that works on low-end Android devices with intermittent connectivity. Key challenges:
Building an offline-first app that syncs when connectivity returns
Integrating NASA POWER climate data for agricultural intelligence
GPS-based farm verification to prevent fraud in loan applications
Calculating farm acreage from GPS polygon boundaries
Supporting local languages (Runyoro/Luganda) for rural farmers
Admin tools for auditing vendor claims and financial risk assessment
The Solution
We built the platform with Firebase for real-time data sync and offline persistence. The Shoelace formula calculates acreage from GPS coordinates mapped by farmers walking their boundaries. The NASA POWER API provides climate insights for crop planning.
The admin audit module flags any farm where self-reported acreage differs from polygon-calculated area by more than 15%, preventing loan fraud. The platform supports three languages and is optimized for devices with as little as 1GB RAM.
Results
Farmers can register and verify farms entirely from their phones
Climate data helps farmers make informed planting decisions
GPS verification reduces loan fraud by validating actual farm sizes
Offline-first design works in areas with no internet