# Constructor
## Configuration
Set up a new `appmixer` instance with `config` parameters and `set`/`get` methods:
```javascript
const appmixer = new Appmixer({/* [name]: value */})
appmixer.set(name, value)
appmixer.get(name)
```
#### **`config.baseUrl`**
Type: `String` | Default: `null`
Base URL of your Appmixer engine REST API.
#### **`config.accessToken`**
Type: `String` | Default: `null`
Access token of an authorized user.
#### **`config.debug`**
Type: `Boolean` | Default: `false`
Enable debugger for development purposes.
#### **`config.theme`**
Type: `Object` | Default: `DefaultTheme`
#### **`config.l10n`**
Type: `Object` | Default: `DefaultL10N`
Define custom localization texts.
#### **`config.lang`**
Type: `String` | Default: `en`
Specify a language code for the localization of components.
#### **`config.api`**
Type: `Object` | Default: `{}`
Set custom API methods.
## Instance
#### **`appmixer.ui`**
```javascript
appmixer.ui('Widget', {/* ... */})
appmixer.ui.Widget({/* ... */})
```
Register and create UI Widgets.
#### **`appmixer.api`**
Use methods of built-in API Module.
#### **`appmixer.set`**
```javascript
appmixer.set(key, value)
```
Set configuration property.
#### **`appmixer.get`**
```javascript
appmixer.get(key, value)
```
Get configuration property.
#### **`appmixer.registerCustomComponentShape`**
```javascript
appmixer.registerCustomComponentShape(name, shape)
```
Register a custom **Designer** component shape.
#### **`appmixer.registerInspectorField`**
```javascript
appmixer.registerInspectorField(type, Field, options)
```
Register a custom **Designer** inspector field.
## Basic Usage
Connect to Appmixer engine REST API and render user interfaces with a built-in widget:
```html
```
{% hint style="info" %}
Change `USERNAME` and `PASSWORD` parameters to valid credentials for registration of a new user.
{% endhint %}
Flow Manager
Learn more about the basic usage with the **Quick Start** example.