An offerwall is an in-app advertising unit where app developers list multiple rewarded ads for app monetization. An offerwall integration can be done via an SDK. It is very popular among mobile games, especially hyper-casual games and RPG games. Mobile game developers use offerwalls by giving level achievement, in-game currencies, and more. It helps them to generate revenue from app monetization.  

In offerwall integration, app users are not disrupted by rewarded ads. Instead, they can reach the list of ads to collect rewards anytime they want via an in-app store or a menu within the app. This is why it is a good app monetization strategy for app developers.