When you create an app, a website, or a game, how do you attract users, and perhaps more importantly, how do you keep them? Irresistible Apps explains exactly how to do this using a library of 27 motivational design patterns and real-world examples of how they work. As a developer, you need to retain users in the new economy of advertisements, subscriptions, and in-app purchases, but how do you do this? How do some applications keep users coming back? Why do people spend hours and hours playing World of Warcraft? Why do people care about Reddit karma? What makes customers keep buying from Amazon? Why do so many people love Khan Academy? The answers are found in Gameful, Social, Interface, and Information patterns. Not only will you learn about these patterns, you'll also learn why they work using psychological theories of intrinsic motivation, behavioral psychology, and behavioral economics. Good and bad implementations of the patterns are shown so practitioners can use them effectively and avoid pitfalls along the way.