Offerwall

An in-app screen listing multiple tasks or offers a user can complete to earn in-app currency or rewards.

The user opens the wall, sees a menu of offers, install this app and reach level five, start a free trial, finish a survey, and picks whichever ones they want. Each completed offer pays out a set amount of your app's currency, and an advertiser pays you for the action on the other side. It is opt-in and self-directed, so it draws the players most willing to grind for currency rather than spend real money. You surface it in your store or economy screen and settle rewards on verified completion.

Picture a mobile RPG where gems are the premium currency. Rather than only selling gem packs, you add an offerwall: a player short on gems completes a "reach level ten in this other game" offer and earns a few hundred gems, the other developer pays for a high-intent installer, and you take the margin without charging your own player anything.

Offerwalls attract fraud and non-payers. The same reward structure that pulls in grinders also pulls in bots and users who never convert, and a poorly filtered wall floods your economy with currency earned by fake completions. People bolt on an offerwall for incremental revenue and inherit a fraud-detection problem they did not budget for.

A wall of free currency draws exactly the users you did not want.