Session counting and the af_app_opened event explained

The af_app_opened event is sent by the AppsFlyer SDK each time an app launches or is displayed in the foreground.

What is its purpose?

AppsFlyer uses the af_app_opened event to count sessions. Session data can be found on the activity page in the dashboard.

The af_app_opened provides advertisers with the ability to record af_app_opened events and attribute them to a particular media source and campaign. The event is sent back as a postback to the ad network.

Sending af_app_opened to ad networks

The af_app_opened event requires no code implementation since it is handled automatically by the Appsflyer SDK. It is available to any network supporting In-App Events. The event value is not relevant for af_app_opened.

Since af_app_opened is a frequently occurring event, it does not appear in any reports (either aggregated or raw).


  • The af_app_opened event is a frequent event and therefore may create a high volume of postbacks.
  • In-App Events Mapping >> Map all SDK events: mapping all events does not include the af_app_opened.

Af_app_opened and retargeting

When existing users re-engage with an app, it starts a period of time called "Re-engagement window". During this window all events, including af_app_opened, are sent to both original network and retargeting network.

However, with Google Ads and Twitter users, to avoid duplicate postbacks, AppsFlyer sends the af_app_opened event once.

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