> ## Documentation Index > Fetch the complete documentation index at: https://docs.mobster.dev/llms.txt > Use this file to discover all available pages before exploring further. # Android > Run Mobster's driver on Android emulators and USB phones. Experimental, behind a flag. Mobster reads an Android screen through `adb` and `uiautomator`, maps it to the same accessibility tree an iPhone gives, and acts with `adb shell input`. Android is experimental: it stays off until you set `MOBSTER_EXPERIMENTAL_ANDROID=1`. A check you wrote for iOS runs on Android with the same `expect` assertions. Android runs launch-only and key-less checks today; Smart steps on Android aren't measured yet. ## Set up You need the Android SDK with platform-tools. For emulators you also need the Android Emulator and one virtual device (AVD). Android Studio installs all of it, about 3 GB. Mobster doesn't install the SDK. ```sh theme={"theme":"css-variables"} export MOBSTER_EXPERIMENTAL_ANDROID=1 mobster sim doctor ``` `mobster sim doctor` adds these rows when the flag is on: Android SDK, adb, Android emulator, Android virtual device, Hardware acceleration and Android devices. Each failing row prints the fix. Mobster finds the SDK at `$ANDROID_HOME`, `$ANDROID_SDK_ROOT`, then `~/Library/Android/sdk`. On a USB phone, turn on Developer options, then USB debugging, plug the phone in and accept the prompt on its screen. A phone that shows `unauthorized` in `adb devices -l` is never used. ## Emulators ```sh theme={"theme":"css-variables"} mobster sim android list # emulators and USB phones mobster sim android boot Pixel_8 # boot headless and hold it for a run mobster sim android shutdown # stop the emulators Mobster booted ``` Mobster boots an emulator with `-no-window -no-audio`, one run at a time per device. `MOBSTER_MAX_SIMS` (default 2) caps the emulators Mobster boots. `shutdown` stops only emulators Mobster booted that aren't running a check; emulators and phones you started yourself are never stopped. ## Run a check ```yaml theme={"theme":"css-variables"} name: settings opens app: bundle: com.android.settings device: Pixel 8 runtime: Android 14 expect: - text: Network & internet ``` ```sh theme={"theme":"css-variables"} mobster test .mobster/checks --android # any idle emulator, else the first AVD mobster test .mobster/checks --android Pixel_8 # an AVD name or an emulator's adb serial ``` Checks run on Android emulators only. A USB Android phone ends the check as couldn't-run before anything is launched, because Mobster can't yet tell your own builds from the other apps on a phone. A check also runs on Android without the flag when `app.path` ends in `.apk` or `runtime` starts with `Android`. `device: Pixel 9` and `runtime: Android 16` pick the AVD whose name starts with the device and whose system image is that release. `app.path` takes an `.apk` (Mobster reads its package name with `aapt2` from the SDK's build-tools); `app.bundle` takes an installed package. Apps that ship with Android (`com.android.*`, `com.google.android.*`) keep their data; others reset like on iOS: `reinstall` for an `.apk`, `data` (`pm clear`) otherwise. | `conditions` key | On Android | | - | - | | `appearance` | `cmd uimode night`, put back after the run | | `locale` | `cmd locale set-app-locales` for the app, Android 13 or later | | `permissions` | `pm grant` and `pm revoke` (`reset` revokes) on an emulator; `calendar`, `contacts`, `location`, `location-always`, `microphone`, `photos`. On a phone they are skipped, and the report says so | | `location` | `adb emu geo fix`, emulators only | | `push`, `content_size`, `increase_contrast`, `route`, `media`, `status_bar`, `network`, and `stubs` | The check is couldn't-run and names the key; it never runs in the wrong state | Fixtures that seed files, the keychain or the pasteboard, and `launch.args` and `launch.env`, make a check couldn't-run on Android. In a coding agent, `list_devices` lists Android devices with `"platform": "android"` (iOS rows say `"ios"`), `verify_start` takes one as `device`, and `run_tests` takes `android`. An emulator is treated like a simulator. A USB phone is treated like an iPhone: `mobster mcp --allow-device` must name it, `app_path` and resets are refused, and Mobster never clears, reinstalls or changes the permissions of an app on it. Driving a device directly with `tap` and `screen` isn't available on Android yet. ## What works | Does | Through | | - | - | | Read the screen as roles, labels, ids, values and frames | `uiautomator dump`, mapped to the iOS tree | | Tap, swipe, type ASCII text, Home, Back, volume | `adb shell input` | | Launch an app, open a link | `monkey`, `am start -a VIEW` | | Install an `.apk` | `adb install -r` | | Screenshot, logcat with secrets masked, crash and ANR detection | `screencap`, `logcat` | | Screen recording up to 3 minutes | `screenrecord` | The tree maps `resource-id` to the id, `text` and `content-desc` to the label, and sizes to dp, so `id:`, `label:` and `role:` selectors read the same on both platforms. ## What doesn't * Typing takes plain ASCII without `%`. Accents and emoji are refused, not mangled. * No push notifications. * The tree comes from `uiautomator dump`, not the Appium UIAutomator2 server. A dump is slower and a screen that animates forever can't be dumped. The server's APKs need a pinned download, which `mobster sim doctor --fix` will do once they are pinned. * System permission dialogs aren't answered yet; grant the permission with `conditions.permissions`. * Crash evidence from `logcat` isn't attached to a report yet. * Video and the Mac app's device list aren't wired. * Checks on a USB Android phone are refused (decided 25 Oct 2026). They stay refused until Mobster can tell your own builds from the other apps on a phone. The device tools still reach a phone that `mobster mcp --allow-device` names. ## Measured 24 Oct 2026, Apple silicon Mac under load 10, Android Studio's Pixel\_8 emulator (API 34, arm64), Settings: | Step | Time | | - | - | | Boot headless | 12.3 and 14.3 s (two runs) | | Launch Settings, wait 2 s, read the screen | 9.3 and 10.4 s | | One `uiautomator dump` mapped to a tree | 2.1 and 2.6 s | The dump time is high because the Mac was busy; measure again on a quiet one before you plan around it. 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