# killApp

The `killApp` command terminates the running application. It is designed specifically for mobile environments to simulate the application being closed.

{% hint style="info" %}
The `killApp` has no effect over Web tests.
{% endhint %}

### Syntax

The `killApp` command can take an optional `appId`. If no `appId` is provided, Maestro targets the application defined in the Flow's header.

```yaml
# Terminates the default app
- killApp

# Terminates a specific app
- killApp: 
    appId: "com.example.otherapp"
```

{% hint style="info" %}

#### Android 

On Android, this command triggers a system-initiated process death, which is equivalent to running `adb shell am kill {package name}`. 
{% endhint %}

### Usage examples

The following example demonstrates how to trigger and recover from a system-initiated process death on Android. This command is useful for testing an application's ability to gracefully launch after being terminated suddenly by the OS.

```yaml
# trigger-process-death.yaml
appId: com.example
---
- pressKey: Home # Puts the app into the background
- killApp # Kills the app via system-initiated process death
- launchApp: # Relaunches the app
    stopApp: false # Don't attempt a clean stop of the app first
```

### Best practices

Maestro team recommends defining the process death commands as a reusable [subflow](https://app.gitbook.com/s/mS3lsb9jRwfRHqddeRXG/flow-control-and-logic/nested-flows) (e.g., `trigger-process-death.yaml`) and calling it via `runFlow` in your tests. This ensures that the screen under test maintains its data after the system-initiated process death.

The following example demonstrates how to verify data persistence:

```yaml
appId: com.example
---
- launchApp

- tapOn:
    id: "com.example:id/enter_name"
- inputText: "John Doe"
- tapOn:
    id: "com.example:id/next"

- assertVisible:
    id: "com.example:id/show_name"
    text: "Name = John Doe"
    enabled: true

- runFlow: trigger-process-death.yaml

- assertVisible:
    id: "com.example:id/show_name"
    text: "Name = John Doe"
    label: "Asserts that \"Name = John Doe\" meaning the screen kept its data after System-initiated Process Death"
    enabled: true
```

### Related commands

* [stopapp](https://docs.maestro.dev/reference/commands-available/stopapp "mention")
* [launchapp](https://docs.maestro.dev/reference/commands-available/launchapp "mention")