Folder Structure Core Principle: Colocation Place code as close to where it's relevant as possible. Things that change together should be located together. Organization Approaches Feature-Based (Recommended for Frontend) Group by domain - all related code in one place: Layer-Based (Common for Backend) Group by technical layer: Monorepo Where to Put Things | Type | Location | |------|----------| | Shared types | or | | Utilities | or (split by domain) | | Config | or root | | Unit tests | Colocate: next to | | E2E tests | or | | Mocks/fixtures | or | Naming Conventions | Type | Convention | |-…