AppsFlyer is a marketing measurement platform made by the company AppsFlyer. Its core product is mobile attribution: finding out which ad, campaign or media source brought each app install, and linking later purchases and other in-app events to that source.
The app sends its installs and events to AppsFlyer through the AppsFlyer SDK (a code library added to the app) or through a server-to-server API. AppsFlyer receives data points from both advertisers and ad networks and joins them into one record, shown in dashboards of installs, events and revenue that update in real time. On iOS, where Apple's privacy rules limit tracking, it works with SKAdNetwork, Apple's framework that reports campaign results without naming the user, and models the conversions it cannot see. Other parts of the platform handle deep linking (links that open a specific screen inside an app), ad fraud protection, and measurement for web, CTV and game consoles.
AppsFlyer is a hosted service. The Zero plan, for apps without paid campaigns, is free. The Growth plan is billed per conversion. An Enterprise plan is also offered.