# iOS (Swift) SDK Configuration Options Reference


The iOS (Swift) SDK provides various configuration options to customize its behavior according to your requirements. This guide covers all the available configuration options and their usage.

## Configuration class

The `Configuration` class is used to initialize the SDK in your Apple platform application. It defines the required parameters and optional configuration settings to customize the SDK behavior.

## SDK configuration options

| Parameter | Type | <div style="width: 300px;">Description</div> |
| :----------| :------------| :-------------|
| `writeKey` <br/> <span style="color: #4D4DFF;font-size:12px;">Required</span> | String | The source write key obtained from the RudderStack dashboard used for authentication. |
| `dataPlaneUrl` <br/> <span style="color: #4D4DFF;font-size:12px;">Required</span> | String | The URL of your RudderStack data plane (backend) where the events are sent. |
| `controlPlaneUrl` | String | URL for remote configuration management. <br /><br />**Default value:**  `https://api.rudderlabs.com` |
| `gzipEnabled` | Boolean | Enables or disables [Gzip compression](#request-compression) for network requests. <br /><br />**Default value:**  `false` |
| `flushPolicies` | Array of flush policies | Specifies when and how events are sent to the RudderStack backend. <br /><br />See [Flush policies in iOS (Swift) SDK]({{< ref "sources/event-streams/sdks/mobile-sdk-apis/flush-api.md#flush-policies" >}}) for more information. <br /><br />**Default value:**  `[StartupFlushPolicy(), FrequencyFlushPolicy(), CountFlushPolicy()]`  |
| `collectDeviceId` | Boolean | Enables [automatic collection](#device-id-collection) of the device's unique ID. <br /><br />**Default value:** `true` |
| `trackApplicationLifecycleEvents` | Boolean | Enables automatic tracking of [application lifecycle events]({{< ref "sources/event-streams/sdks/client-side-features/lifecycle-events-tracking.md" >}}) (app start, background, and foreground transitions). <br /><br />**Default value:** `true`  |
| `sessionConfiguration` | SessionConfiguration | Configuration settings for managing user sessions. <br /><br /><ul><li>See [Session Tracking]({{< ref "sources/event-streams/sdks/client-side-features/session-tracking.md" >}}) for more information on session management in the iOS (Swift) SDK.</li><li>See [Session configuration](#session-configuration) for more information on the session configuration options and their default values.</li></ul> |

## Session configuration

The `SessionConfiguration` class provides the following parameters to customize session management:

| Parameter | Type | <div style="width: 300px;">Description</div> | 
| :----------| :------------| :-------------| 
| `automaticSessionTracking` | Bool | Enables automatic session tracking. <br /><br /> **Default value:** `true` |
| `sessionTimeoutInMillis` | UInt64 | Sets the timeout duration for automatic session tracking in milliseconds. It is the time between the app closed or backgrounded to being foregrounded or relaunched again. <br /><br />The SDK times out a session and starts a new session after this time has elapsed. <br /><br />**Default value:** `300000` (5 minutes) |
| `updateSessionOnBackgroundEvents` | Bool | When `false`, background events do not extend the session lifetime. Set to `true` to allow background events to extend the session lifetime. <br /><br />See the [Session tracking]({{< ref "sources/event-streams/sdks/client-side-features/session-tracking.md#configuration-parameters" >}}) guide for details. <br /><br />**Default value:** `false` |

## Device ID collection

When you enable `collectDeviceId`, the iOS (Swift) SDK retrieves a unique device ID and includes it in the event payload under the `device.id` field in the event's `context` object.

In the iOS, watchOS, and tvOS platforms, the SDK uses the device’s `identifierForVendor` field. In macOS, it derives the ID from the device’s MAC address.

{{< warning >}}
If the SDK retrieves an empty or invalid value for the device ID, it will not include the `device.id` field in the event payload's `context`.
{{< /warning >}}

## Request compression

When you set `gzipEnabled` to `true`, all `/batch` requests sent by the SDK will have their payloads compressed using Gzip compression, thereby reducing the size of the network requests.

## Sample SDK initialization

The following snippet demonstrates how to initialize the iOS (Swift) SDK with the supported configuration options:

{{< tabs tabTotal="2" >}}
{{% tab tabName="Swift" %}}
```swift
let analytics = Analytics(
    configuration: Configuration(
        // Required parameters
        writeKey: "YOUR_WRITE_KEY",
        dataPlaneUrl: "YOUR_DATA_PLANE_URL",
        
        // Optional parameters
        controlPlaneUrl: "https://api.rudderlabs.com",
        gzipEnabled: true,
        flushPolicies: [
            StartupFlushPolicy(),
            CountFlushPolicy(flushAt: 20),
            FrequencyFlushPolicy(flushIntervalInMillis: 30000)
        ], // Sets custom flush policies
        collectDeviceId: true,
        trackApplicationLifecycleEvents: true,
        sessionConfiguration: SessionConfiguration(
            automaticSessionTracking: true,
            sessionTimeoutInMillis: 300000 // 5 minutes
        )
    )
)
```
{{% /tab %}}
{{% tab tabName="Objective-C" %}}
```objectivec
RSSConfigurationBuilder *builder = [[RSSConfigurationBuilder alloc]
// Required parameters
          initWithWriteKey:@"YOUR_WRITE_KEY"
					dataPlaneUrl:@"YOUR_DATA_PLANE_URL"];
					
// Optional parameters
[builder setControlPlaneUrl: @"https://api.rudderlabs.com"];
[builder setGzipEnabled: YES];
[builder setFlushPolicies: @[
        [RSSStartupFlushPolicy new],
        [[RSSCountFlushPolicy alloc] initWithFlushAt: 20],
        [[RSSFrequencyFlushPolicy alloc] initWithFlushIntervalInMillis: 30000]
]];
[builder setCollectDeviceId: YES];
[builder setTrackApplicationLifecycleEvents: YES];

// Prepare Session Configuration
RSSSessionConfigurationBuilder *sessionBuilder = [RSSSessionConfigurationBuilder new];
[sessionBuilder setAutomaticSessionTracking: YES];
[sessionBuilder setSessionTimeoutInMillis: @30000];
    
[builder setSessionConfiguration: [sessionBuilder build]];

RSSAnalytics *analytics = [[RSSAnalytics alloc] 
																			initWithConfiguration:[builder build]];
```
{{% /tab %}}
{{< /tabs >}}