Composting Platform | John Wilker

Overview

API (Fastify, Prisma, PostgreSQL) for farms and leira measurements; JWT auth and roles (USER, ADMIN, MASTER, DEV). Mobile app (Expo, React Native, Redux Toolkit, NativeWind) with offline storage (Expo SQLite) and automatic sync when online. Optional Google Sheets integration for Masters.

Problem

Field workers need to record compost measurements (temperature, humidity, smell, phase) often without reliable connectivity. Data must sync when back online and align with a central API and optional spreadsheets.

Solution

Backend: REST API with signup/signin, farms CRUD, measurements CRUD, and sync endpoints (upload/download). Mobile: login, dashboard, farms and measurements lists, create/edit measurements offline; auto-sync with conflict handling. Optional Google Sheets worksheet per Master for reporting.

Tech Stack

ExpoReact NativeRedux ToolkitRedux PersistNativeWindExpo SQLiteFastifyPrismaPostgreSQLJWTZodGoogle Sheets APISentry

Architecture

Backend: use-cases (auth, farms, measurements, sync), repositories, controllers, JWT plugin. Mobile: Expo Router tabs, store slices (auth, farm, measurement, sync), SQLite repositories, sync service. See the architecture section for database model and diagrams.

View architecture

Screenshots

Screenshots from the real workflow. UI copy is in Portuguese because the first release was designed for a Brazilian audience (PT-BR).

Login

Dark theme

Measurements list mockup — dark theme — Measurements

New measurement (USER) mockup — dark theme — New measurement (USER)

Create farm (DEV) mockup — dark theme — Create farm (DEV)

Create leiras (DEV) mockup — dark theme — Create leiras (DEV)

Create user (MASTER) mockup — dark theme — Create user (MASTER)

Light theme

Measurements list mockup — light theme — Measurements

New measurement (USER) mockup — light theme — New measurement (USER)

Create farm (DEV) mockup — light theme — Create farm (DEV)

Create leiras (DEV) mockup — light theme — Create leiras (DEV)

Create user (MASTER) mockup — light theme — Create user (MASTER)