Phase

Framework (OSS). Guide for creating and writing Expo native modules and views using the Expo Modules API (Swift, Kotlin, TypeScript). Covers module definition DSL, native views, shared objects, config plugins, lifecycle hooks, autolinking, and type system. Use when building or modifying native modules for Expo. Not for migrating an existing Swift module from the definition DSL to the Expo Modules API 2.0 macros; use expo-migrate-module (from the expo-experiments plugin) for that.

Framework (OSS). Navigation and routing for Expo Router. Covers file-based routes, groups and dynamic routes, folder organization, Link with previews and context menus, native Stack, page titles, modals and form sheets, NativeTabs, headers and toolbars, and header search bars.

Framework (OSS). Build native UI with the @expo/ui package: real SwiftUI on iOS and Jetpack Compose on Android rendered from React in an Expo or React Native app. Covers universal cross-platform components (Host, Column, Row, Button, Text, List, and more imported from @expo/ui), drop-in replacements for popular React Native community libraries (BottomSheet, DateTimePicker, Slider, Menu, etc.), and platform-specific SwiftUI (@expo/ui/swift-ui, iOS only) and Jetpack Compose (@expo/ui/jetpack-compose, Android only) trees and modifiers. Use when adding or reviewing @expo/ui Host/RNHostView trees, building native-feeling UI where standard React Native components fall short (grouped settings forms with toggles, sections, menus, sheets, pickers, sliders), choosing between universal and platform-specific components, or replacing an RN community UI library with a native @expo/ui equivalent. Not for custom native modules, Expo Router navigation, Reanimated, or data fetching.

React and Next.js performance optimization guidelines from Vercel Engineering. This skill should be used when writing, reviewing, or refactoring React/Next.js code to ensure optimal performance patterns. Triggers on tasks involving React components, Next.js pages, data fetching, bundle optimization, or performance improvements.