# Configuration Options

The SDK consists of a few packages. You’ll get the most value out of Customer.io when you use all our packages together, but this lets you omit packages for features you don’t intend to use.

You’ll call configuration options before you initialize the SDK with `CustomerIOConfig`. When you initialize the SDK, you can pass configuration options. In most cases, you’ll want to stick with the defaults, but you might do things like change the `logLevel` when testing updates to your app.

```dart
CustomerIO.initialize(
  config: CustomerIOConfig(
    cdpApiKey: "YOUR_CDP_API_KEY", // Required
    migrationSiteId: "YOUR_SITE_ID", // Required to migrate from a previous version
    autoTrackDeviceAttributes: true,
    region: Region.us,
    logLevel: CioLogLevel.error
  )
);
```

Option

Type

Default

Description

`cdpApiKey`

string

**Required**: the key you'll use to initialize the SDK and send data to Customer.io

`region`

`eu` or `us`

`us`

**Required if your account is in the EU region**.

`apiHost`

string

The domain you’ll proxy requests through. You’ll only need to set this (and `cdnHost`) if you’re [proxying requests](#proxying-requests).

`autoTrackDeviceAttributes`

boolean

`true`

Automatically gathers information about devices, like operating system, device locale, model, app version, etc

`cdnHost`

string

The domain you’ll fetch configuration settings from. You’ll only need to set this (and `apiHost`) if you’re [proxying requests](#proxying-requests).

`logLevel`

string

`error`

Sets the level of logs you can view from the SDK. Set to `debug` or `info` to see more logging output.

`migrationSiteId`

string

**Required if you're updating from 1.x**: the credential for previous versions of the SDK. We use this key to send remaining tasks to Customer.io when your audience updates your app.

`screenViewUse`

`All` or `inApp`

`all`

`ScreenView.all` (Default): Screen events are sent to Customer.io. You can use these events to build segments, trigger campaigns, and target in-app messages.  
  
`ScreenView.InApp`: Screen view events not sent to Customer.io. You’ll *only* use them to target in-app messages based on page rules.

`trackApplicationLifecycleEvents`

boolean

`true`

Set to `false` if you don’t want the app to send [lifecycle events](/integrations/sdk/flutter/tracking/lifecycle-events) like `Application Opened`

`inApp.siteId`

string

Used to initialize the `inApp` package, and determines the workspace your in-app messages come from.

`push.android.pushClickBehavior`

string

`activityPreventRestart`

One of `resetTaskStack`, `activityPreventRestart`, `activityNoFlags`; determines how to handle push clicks.

`locationConfig`

object

Enable [location tracking](/integrations/sdk/flutter/tracking/location/). Takes a `trackingMode` option using the `LocationTrackingMode` enum.

## Proxying requests[](#proxying-requests)

By default, requests go through our domain at `cdp.customer.io`. You can proxy requests through your own domain to provide a better privacy and security story, especially when submitting your app to app stores.

To proxy requests, you’ll need to set the `apiHost` and `cdnHost` properties in your `SDKConfigBuilder`. While these are separate settings, you should set them to the same URL.

While you need to initialize the SDK with a `cdpApiKey`, you can set this to any value you want. You only need to pass your actual key when you send requests from your server backend to Customer.io. If you want to secure requests to your proxy server, you can set the `cdpApiKey` to a value representing basic authentication credentials that you handle on your own. See [proxying requests](/integrations/data-in/proxying-requests) for more information.

```dart
CustomerIO.initialize(
  config: CustomerIOConfig(
    cdpApiKey: "YOUR_CDP_API_KEY",
    apiHost: "YOUR_PROXY_HOST",
    cdnHost: "YOUR_CDN_HOST",
    region: Region.us,
    logLevel: CioLogLevel.error
  )
)
```