> ## Documentation Index
> Fetch the complete documentation index at: https://docs.activeviam.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Extending the app

<a id="module-docs.pages.extending_the_app" />

<Note>
  This feature is not part of the community edition: it needs to be [unlocked](./unlocking_all_features).
</Note>

Both the server and the embedded UI can be extended.

## Server extension

[Atoti Server extensions are developed in Java](https://docs.activeviam.com/products/atoti/server/6.2/docs/starters/atoti_server_extension) and packaged as [`JARs`](../api/atoti.config.session_config#atoti.SessionConfig.extra_jars).
They can register:

* measure plugins which can then be used in Python with [`atoti.plugin_measure()`](../api/atoti.function.plugin_measure#atoti.plugin_measure).
* Spring webservices.

## UI extension

Atoti UI extensions are developed in JavaScript/TypeScript.
They can change the behavior of the web app or augment it with new features.

### Branding

The Atoti branding can be replaced with a custom one (also called white-labeling):

```pycon theme={"languages":{"custom":["/engine/python-sdk/0.9/languages/pycon.tmLanguage.json"]}}
>>> from pathlib import Path
```

```pycon theme={"languages":{"custom":["/engine/python-sdk/0.9/languages/pycon.tmLanguage.json"]}}
>>> import atoti as tt
```

```pycon theme={"languages":{"custom":["/engine/python-sdk/0.9/languages/pycon.tmLanguage.json"]}}
>>> resources_directory = Path("__resources__") / "extending_the_app"
```

```pycon theme={"languages":{"custom":["/engine/python-sdk/0.9/languages/pycon.tmLanguage.json"]}}
>>> session_config = tt.SessionConfig(
...     branding=tt.BrandingConfig(
...         favicon=resources_directory / "favicon.ico",
...         logo=resources_directory / "logo.svg",
...         title="Hey hey hey",
...     ),
... )
```

```pycon theme={"languages":{"custom":["/engine/python-sdk/0.9/languages/pycon.tmLanguage.json"]}}
>>> session = tt.Session.start(session_config)  
```

The app of this session looks like this:

<img src="https://mintcdn.com/activeviam/Eh3Su73oAmRCnbdN/engine/python-sdk/6.2.0b0/guides/__resources__/extending_the_app/rebranded.png?fit=max&auto=format&n=Eh3Su73oAmRCnbdN&q=85&s=6b2f953aa45b1da96554dbd2a363b963" alt="Rebranded app" width="2036" height="1394" data-path="engine/python-sdk/6.2.0b0/guides/__resources__/extending_the_app/rebranded.png" />

### UI app extension

There are some prebuilt extensions in [`atoti.app_extension`](../api/atoti.app_extension#module-atoti.app_extension).
For instance:

```pycon theme={"languages":{"custom":["/engine/python-sdk/0.9/languages/pycon.tmLanguage.json"]}}
>>> session_config = tt.SessionConfig(app_extensions=tt.ADVANCED_APP_EXTENSION)
```

```pycon theme={"languages":{"custom":["/engine/python-sdk/0.9/languages/pycon.tmLanguage.json"]}}
>>> session = tt.Session.start(session_config)  
```

This extension will add some advanced tools and a **Text editor** widget:

<img src="https://mintcdn.com/activeviam/Eh3Su73oAmRCnbdN/engine/python-sdk/6.2.0b0/guides/__resources__/extending_the_app/extended.png?fit=max&auto=format&n=Eh3Su73oAmRCnbdN&q=85&s=6709684bbc5b9cf3acf6f6c95ee903b8" alt="Extended app" width="2036" height="1394" data-path="engine/python-sdk/6.2.0b0/guides/__resources__/extending_the_app/extended.png" />

Take a look at the documentation of [`atoti.SessionConfig.app_extensions`](../api/atoti.config.session_config#atoti.SessionConfig.app_extensions) to learn how to create your own extensions.