In-app purchase (IAP)

An in-app purchase is a transaction made from inside a mobile app for digital goods, extra content, virtual currency, or a subscription, processed through the platform's built-in payment system on most storefronts. It is the primary monetization mechanism for free-to-download apps, particularly games and content or utility apps offering premium tiers.

IAP revenue is typically analyzed through metrics like average revenue per daily active user and conversion rate from free user to paying user, since only a fraction of an app's user base usually ever makes a purchase. It differs from a standard e-commerce transaction, captured in metrics like average order value or gross merchandise value, mainly in the payment infrastructure and platform rules involved — many app stores require digital goods to be sold through their own in-app purchase system rather than an external checkout, and take a revenue share on those transactions.

IAP matters because it determines the unit economics of free-to-play and freemium apps, where the small share of paying users has to support the cost of acquiring and serving the much larger free user base. Common pitfalls include analyzing IAP revenue without segmenting by paying-user cohort, which hides how spend concentrates among a small number of high-value users, and conflating one-time purchases with recurring subscription revenue, which behave very differently over time and are usually tracked separately.