# Expo Brownfield

Integrate Expo and React Native into an existing native iOS or Android app.

- Repository: https://github.com/expo/skills (4005 stars)
- Category: Design
- License: MIT
- Last updated: 2026-11-01
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add expo/skills --skill expo-brownfield -g -a claude-code -y`
Codex: `npx skills add expo/skills --skill expo-brownfield -g -a codex -y`
Cursor: `npx skills add expo/skills --skill expo-brownfield -g -a cursor -y`
Gemini CLI: `npx skills add expo/skills --skill expo-brownfield -g -a gemini-cli -y`
Claude Code plugin marketplace: `/plugin marketplace add expo/skills`

## Description

Integrate Expo and React Native into an existing native iOS or Android app. Use for brownfield, embedding a React Native screen in SwiftUI/UIKit or Kotlin, or AAR/XCFramework packaging. Covers isolated and integrated approaches. For building or distributing a purely native app with EAS, use eas-app-stores.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# Expo Brownfield

A **brownfield** app is an existing native iOS or Android app that adopts React Native incrementally, as opposed to a **greenfield** app that is React Native from day one.

## Inspect the host first

Identify the existing app entry point, navigation owner, native build system, deployment targets, and any React Native runtime already linked. Record the installed Expo, React Native, and brownfield package versions from the lockfile. Adding EAS Build or Submit to a Swift app alone does not require React Native; route that task to `eas-app-stores`.

Preserve the host's SwiftUI `App` / UIKit window and native screens when embedding a feature. **Do not run prebuild in a manually maintained native host**, including during troubleshooting. An isolated Expo producer may use CNG; keep its generated `ios/` and `android/` separate from the consuming app.

Expo supports two distinct ways to add React Native to a brownfield project:

| Approach       | What ships to the native app                                        | When to choose                                                                   |
| -------------- | ------------------------------------------------------------------- | -------------------------------------------------------------------------------- |
| **Isolated**   | Prebuilt AAR / XCFramework                                          | Native team doesn't need Node or RN tooling; RN code can live in a separate repo |
| **Integrated** | React Native sources added to the existing Gradle / CocoaPods build | One team owns everything; comfortable with RN tooling; wants a single build      |

For the full decision matrix, see [./references/comparison.md](./references/comparison.md).

## Pick an approach

Use these quick rules, fall through to `comparison.md` for anything ambiguous.

The rest: https://github.com/expo/skills/blob/HEAD/plugins/expo/skills/expo-brownfield/SKILL.md