What is a session?

A session is a group of user interactions with your website or mobile app within a given time frame. It is usually triggered when a user opens a mobile app or a website in their browser and ends after a particular period of inactivity.

Session tracking in RudderStack

You can use RudderStack's session tracking feature to determine the average time users spend on an app and how they engage with it. By combining the session metadata with the usage data like event tracking, you can better understand the user's product journey and analyze their behavior effectively. You can also use the resulting insights to identify problems and optimization opportunities in your product workflow.

The following RudderStack SDKs support the session tracking feature:

If the session tracking feature is enabled, you can expect the following properties in your event's context object:

• sessionId (Number): The unique session ID.
• sessionStart (Boolean): Present in the first event, indicating the start of the session.

Automatic session tracking

By default, the above-mentioned RudderStack SDKs automatically track the user sessions. This means that RudderStack automatically determines the start and end of a session depending on the inactivity time configured in the SDK.

JavaScript SDK

In case of the JavaScript SDK, RudderStack considers the SDK initialization as the start of a user session.

To disable automatic session tracking, you can set the load option autoTrack to false, as shown:

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rudderanalytics.load(WRITE_KEY, DATA_PLANE_URL, {
  sessions: {
    autoTrack: false,  // Set to false to disable automatic session tracking
  },
  ...<otherLoadOptions>
});

By default, a session is active until 30 minutes of inactivity have elapsed since the last received event. However, you can adjust this limit using the timeout load option, as shown:

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rudderanalytics.load(WRITE_KEY, DATA_PLANE_URL, {
  sessions: {
    autoTrack: true,
    timeout: 10 * 60 * 1000,  // 10 min in milliseconds
  },
  ...<otherLoadOptions>
});

Every time a new event is generated (track, page, identify, etc.), the SDK resets the session expiration time by adding the configured timeout (default 30 minutes) to the last received event's timestamp.

Mobile SDKs

Android

By default, automatic session tracking is enabled in the Android SDK, as shown:

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val rudderClient = RudderClient.getInstance(
    this,
    WRITE_KEY,
    RudderConfig.Builder()
        .withDataPlaneUrl(DATA_PLANE_URL)
        .withAutoSessionTracking(true)  // Set to false to disable automatic session tracking
        .withSessionTimeoutMillis(5*60*1000)
        .build()
)

Copy
RudderClient rudderClient = RudderClient.getInstance(
    this,
    WRITE_KEY,
    new RudderConfig.Builder()
        .withDataPlaneUrl(DATA_PLANE_URL)
        .withAutoSessionTracking(true) // Set to false to disable automatic session tracking
        .withSessionTimeoutMillis(5*60*1000)
        .build()
);

To disable automatic session tracking, set withAutoSessionTracking to false.

iOS

By default, automatic session tracking is enabled in the iOS SDK, as shown:

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RSConfigBuilder *builder = [[RSConfigBuilder alloc] init];
[builder withDataPlaneUrl:DATA_PLANE_URL];
[builder withAutoSessionTracking:YES];  // Set to No to disable automatic session tracking
[builder withSessionTimeoutMillis:(5*60*1000)];
[RSClient getInstance:WRITE_KEY config:[builder build]];

Copy
let builder: RSConfigBuilder = RSConfigBuilder()
            .withDataPlaneUrl(DATA_PLANE_URL)
            .withAutoSessionTracking(true)  // Set to false to disable automatic session tracking
            .withSessionTimeoutMillis(5*60*1000)
RSClient.getInstance(WRITE_KEY, config: builder.build())

To disable automatic session tracking, set withAutoSessionTracking to false.

Session expiration in mobile SDKs

By default, a session is active until 5 minutes of inactivity have elapsed. However, you can adjust this limit using the sessionTimeoutMillis load option, as seen in the above snippets.

If the duration between the last received event and the next Application Opened event is more than sessionTimeoutMillis, RudderStack starts a new session. Otherwise, it continues the previous session.

Manual session tracking

RudderStack also supports manual session tracking using the following methods that indicate the start and end of a user session:

Session tracking flow

The following sections describe how the session tracking works in the RudderStack SDKs.

JavaScript SDK

If session tracking is enabled in the JavaScript SDK, the flow is as explained below:

1. During the initialization, the SDK checks for an existing user session. If no valid session exists, it creates a new session. Otherwise, the SDK proceeds with the existing session.
2. Upon receiving an event, the SDK fetches the sessionId. If no valid sessionId is found, it creates a new session and returns the sessionId.
   • If this is the first event of the session, the SDK also sends another parameter in the context called sessionStart: true.

3. Finally, the SDK updates the session expiration time, that is, the last event's timestamp + timeout (default 30 minutes).

The following diagram summarizes the workflow:

Mobile SDKs

If session tracking is enabled in the mobile SDKs, the flow is as explained below:

1. RudderStack starts the session once it receives the Application Opened, Application Installed, or Application Updated event.
2. The SDK then generates a sessionId.

3. The SDK records the user events and the session is active until more than sessionTimeoutMillis (default 5 minutes) of inactivity have elapsed since the last received event.

The following diagram summarizes the workflow:

Supported downstream tools

RudderStack supports forwarding the sessionId and sessionStart fields to the following downstream destinations:

It is important to note the following:

• RudderStack passes the sessionId to the subsequent events in the context.sessionId field.
• RudderStack sets the context.sessionStart field to true in the first event to indicate the start of the session.

FAQ

Refer to the Session Tracking FAQ guide for a comprehensive list of questions on session tracking.