## Compatibility

- Cognigy xApps are compatible with the [supported browsers and channels](https://docs.cognigy.com/xApps/supported-browsers-and-channels).

## Concepts

### Session Concept

An xApp Session can be accessed via the URL and be initialized via the [xApp: Init Session](https://docs.cognigy.com/ai/agents/develop/node-reference/xApp/init-xApp-session) Flow Node. The xApp Session displays a sequence of xApp pages that can be configured as desired. A maximum of one xApp Session can be initialized per Cognigy Session.

### Screen Concept

The Shell Page has a set of configurable built-in screens. These default screens can be used to interact with end users, for example, when the xApp content is not displayed. These default screens are part of the Shell Page, which holds the connection to the Cognigy.AI backend.

#### xApp Screen

The xApp Screens are shown when the xApp page is launched, fails to launch, encounters an Error, and is halted.

#### Intermediate Screen

The Intermediate Screens are displayed to the end user while no xApp page is configured to be displayed. The default Intermediate Screen can be replaced with a custom-built xApp page.

#### Connection Screen

The Connection Screens are shown while the real-time connection to the backend is re-established. The default Connection Screen can be replaced with a custom-built xApp page.

#### PIN Screen

The PIN Screen prompts the end user to enter the xApp Session PIN. The user needs to provide the correct PIN to access the xApp pages. Requesting a PIN to enter the session is optional.

## How it Works

To learn more about how an xApp works, read the [Use cases](https://docs.cognigy.com/xApps/use-cases) and [Build your first xApp](https://docs.cognigy.com/xApps/build/first-xApp) articles.
You can find ready-made examples of xApps in the [Cognigy GitHub](https://github.com/Cognigy/xApps/tree/main) repository.

## More Information

- [Architecture](https://docs.cognigy.com/xApps/architecture)
- [xApp Nodes](https://docs.cognigy.com/ai/agents/develop/node-reference/xApp/overview)
- [xApp Tokens](https://docs.cognigy.com/xApps/tokens)
- [xApp Flow API](https://docs.cognigy.com/xApps/api)