---
title: Introduction
author: Alfonz Homolík
sidebar_position: 0
---

# Applet JS SDK

Applet JS SDK provides the device's native features and functionalities with a unified API for all supported platforms. This SDK is only usable
inside [signageOS applets](https://docs.signageos.io/hc/en-us/articles/4405068855570-Introduction-to-Applets) and allows you to create
lightweight applets and deploy them on any device.

```ts title="Simple example of Applet
import sos from '@signageos/front-applet';

sos.onReady(async () => {
	await sos.management.audio.setVolume(75);
});
```

## Getting started
This section refers to the JS SDK API reference and provides detailed information for every function, including rich examples.

To develop an applet using the Applet JS SDK, you need to install our [CLI](https://developers.signageos.io/docs/cli-setup) and follow our guide [Getting started with Applets](https://developers.signageos.io/docs/applets/getting-started/).

## API Reference
The JS API reference is divided into two main sections:
- `sos` - Main object which contains APIs for controlling video playback, streams, or serial ports.
- `sos.management` - This section contains management APIs for controlling the device's features like audio, network, Wi-Fi, etc.

You can also check our public examples on [GitHub](https://github.com/signageos/applet-examples/)