expo-device-hub

Expo Device Hub is an Expo DevTools plugin that lets you preview and control your iOS simulators and Android emulators right from the browser — without leaving your development workflow. When you run expo start, the Hub adds a device dashboard where you can watch a live stream of any device, interact with it, and manage which devices are running from one place.

Features

• Live stream of iOS simulators and Android emulators in your browser.
• Interact directly — tap, swipe, scroll, and type into the device.
• Boot, shut down, and add devices without opening Xcode or Android Studio.
• Follows your system light/dark theme, and can flip the device's appearance too.

iOS simulators require macOS with Xcode. Android emulators require the Android SDK (emulator, adb).

Use in an Expo app

Using the Hub inside an Expo app requires Expo SDK 57 or newer.

Install the plugin:

npx expo install expo-device-hub

Then start your project as usual:

npx expo start

Expo Device Hub registers itself as a DevTools plugin, so a link to it appears in your terminal when the dev server starts:

› Expo Device Hub: http://localhost:8081/_expo/plugins/expo-device-hub

Use standalone

The Hub also runs outside of expo start as a standalone server — useful when you want the device dashboard without a running Expo project:

npx expo-device-hub

Repository structure

This is a Bun workspace orchestrated with Turborepo.

Package	What it is
packages/expo-device-hub	The main DevTools plugin.
packages/@expo/hub-client	Device-client hooks and types that own the connection to serve-sim / serve-emu and paint the live stream. See hub-client below.
packages/@expo/hub-components	Dependency-free UI kit (Sidebar, StreamPanel, Button, …) built on @expo/styleguide design tokens, so Hub matches the Expo dashboard website.
packages/@expo/hub-apple-utils	Lists, creates, and boots Apple simulator devices via simctl (macOS only).
packages/@expo/hub-android-utils	Lists, creates, and boots Android emulators via avdmanager / sdkmanager / emulator.
packages/expo-serve-emu	Thin wrapper of serve-emu. To be replaced by @expo/serve-emu.
packages/serve-sim	Vendored fork of serve-sim. To be replaced by @expo/serve-sim.
packages/serve-emu	Vendored fork of serve-emu. To be replaced by @expo/serve-emu.
example	A minimal Expo app with the plugin installed.

Getting started

Install dependencies and build every package once from the repo root:

bun install
bun run build   # turbo build across all packages

Run the example

The example app is a host Expo project that has expo-device-hub installed as a DevTools plugin. Use it to see the Hub exactly as an end user would.

cd example
bun start       # or: bun run ios / bun run android / bun run web

Develop

To iterate on the dashboard UI with Metro fast refresh, run expo-device-hub as a standalone Expo web app:

cd packages/expo-device-hub
bun start          # expo start --web, on port 8081

This serves the Dashboard component directly, so edits to the UI hot-reload without going through a host app. A local "inception" DevTools module (modules/expo-device-hub) registers the plugin against itself, so the standalone app still gets the real /api/devices backend while you develop.

The device server is bundled (see scripts/build-plugin-server.ts), so hot reload covers the UI. After changing anything under src/server, rebuild it with bun run build:server.

hub-client

@expo/hub-client is the device-client layer. The two backends speak very different wire protocols — serve-sim streams MJPEG/H.264 and takes binary touch packets, while serve-emu streams H.264 (WebCodecs) and takes JSON gestures — so this package hides that behind one shared contract:

• a hook (useIosDeviceClient / useAndroidDeviceClient and general useActiveDeviceClient) that owns the WebSocket connection and exposes the live connection state plus input controls, and
• a DeviceScreen component that paints whichever stream is active and forwards pointer/gesture/keyboard input.

It lives in its own package (rather than inside the plugin) so the Expo dashboard website can consume the exact same code to mirror devices in the browser.