# Kotlin Conventions

## Language Features
- Use Kotlin 2.x with coroutines for async work
- Prefer data classes for DTOs and value objects
- Use sealed classes/interfaces for domain errors
- Extension functions over utility classes

## Spring Boot
- Constructor injection (no field injection)
- Use @ConfigurationProperties over @Value
- Prefer WebFlux for reactive endpoints
- Use Spring Security with method-level security

## Testing
- JUnit 5 with Kotest assertions
- MockK for mocking (not Mockito)
- Testcontainers for integration tests
- Use @Nested for test organization

---
description: React component conventions and patterns
globs: "*.tsx,*.jsx"
alwaysApply: false
---
# React Component Rules

1. Use functional components with TypeScript interfaces for props
2. Prefer server components by default — add "use client" only for interactivity
3. Colocate component tests in adjacent __tests__/ directories
4. Use named exports, not default exports
5. Extract custom hooks into hooks/ directory when reused across components

## Styling
- Use Tailwind CSS v4 utility classes
- Follow mobile-first responsive design
- Keep component-specific styles colocated

## State Management
- Use React 19 use() for async data in server components
- Prefer URL state (searchParams) over client state where possible
- Use Zustand for complex client-side state