> For the complete documentation index, see [llms.txt](https://docs.appflowy.io/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.appflowy.io/docs/documentation/software-contributions/architecture/backend/initialize.md).

# Initialize

FlowySDK works as the AppFlowy application Backend. It will be initialized before the application launch. Check out the initialization sequence diagram shown below.

![file : flowy\_sdk.plantuml](https://raw.githubusercontent.com/AppFlowy-IO/docs/main/uml/output/FlowySDK-Initialization.svg)

1. FlowyRunner will get called when the entry point, the `main` function, got called.
2. FlowyRunner call `initialize` function on each task that registers as a LaunchTask one by one.
3. `InitRustSDKTask` calls the init function and passes the working directory into FlowySDK.

   ```dart
    getIt<FlowySDK>().init(directory)
   ```

   The directory is different according to the `IntegrationMode`, which means running AppFlowy on developing mode will not alter the data on release mode.

   1. IntegrationMode.release

   ```dart
    Directory documentsDir = await getApplicationDocumentsDirectory();
    final directory = Directory('${documentsDir.path}/flowy')
   ```

   1. IntegrationMode.develop

   ```dart
    Directory documentsDir = await getApplicationDocumentsDirectory();
    final directory = Directory('${documentsDir.path}/flowy_dev')
   ```

   1. IntegrationMode.test

   ```dart
    final directory = Directory("${Directory.current.path}/.sandbox")
   ```
4. `InitAppWidgetTask` initialize the `ApplicationWidget` and call `runApp` function.
5. `InitPlatformServiceTask` start the `NetworkListener`.

## WIP

typing...💬️


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