Got RESTful APIs? Great. API consumers love them. But today, such RESTful APIs are not enough for the evolving expectations of API consumers. Their apps need to be responsive, event-based and react to changes in near real-time. This results in a new set of requirements for the APIs, which power the apps. APIs now need to provide concepts such as events, notifications, triggers, and subscriptions. These concepts are not natively supported by the REST architectural style. The good thing: we can engineer RESTful APIs that support events with a webhook infrastructure. The bad thing: it requires some heavy lifting. The webhook infrastructure needs to be developer-friendly, easy to use, reliable, secure and highly available. With the best practices and design templates provided in this book, we want to help you extend your API portfolio with a modern webhook infrastructure. So you can offer both APIs and events that developers love to use.