Why and When Monorepo Architecture
After a month of building Profit Pilot's web app, I started working on the mobile version to keep both platforms moving in parallel. This is where most projects face a critical decision: 1. Build everything twice (double the time, double the cost) 2. Architect once, deploy everywhere I chose option 2—even with both apps still in active development. My approach: Instead of maintaining two separate codebases, I engineered a unified architecture that powers both platforms simultaneously with enterprise-grade scalability. The architecture: → Turborepo monorepo for lightning-fast builds and intelligent caching → Shared TypeScript types with strict type safety across all packages → Centralized business logic - write once, run everywhere → Platform-optimized auth (secure session cookies for web, JWT with refresh tokens for mobile) → Shared UI component library maximizing code reuse → Real-time sync between platforms using optimistic updates → Automated CI/CD pipeline deploying to both platforms simultaneously → Environment-agnostic API layer with consistent error handling The technical edge: → 70%+ code sharing between platforms → Type-safe API calls with auto-generated clients → Single source of truth for business logic and validation → Consistent user experience across all devices → One security audit, one performance optimization—both platforms benefit Tech stack:Next.js 14 (web) | React Native/Expo (mobile) | Turborepo | MongoDB Atlas | TypeScript | tRPC/REST API | React Query | Zod validation