// GOOD: Parallel when independent
const [users, markets, stats] = await Promise.all([
  fetchUsers(),
  fetchMarkets(),
  fetchStats()
])

// BAD: Sequential when unnecessary
const users = await fetchUsers()
const markets = await fetchMarkets()
const stats = await fetchStats()

// GOOD: Proper types with union for status
interface Market {
  id: string
  name: string
  status: 'active' | 'resolved' | 'closed'
  created_at: Date
}

function getMarket(id: string): Promise<Market> { }

src/
├── index.ts           # Entry point
├── types/             # TypeScript types
├── lib/               # Utilities and helpers
├── services/          # Business logic
└── handlers/          # Request handlers