Event-driven APIs facilitate real-time and asynchronous communication between system components, enhancing user experience by reducing server polling and allowing for loosely-coupled interactions. These APIs operate through a publisher-subscriber model, where events are sent to a message broker and distributed to interested subscribers, as illustrated by a chat application example. AsyncAPI is a specification designed to define the structure and behavior of event-driven APIs, offering a standardized method to describe events, channels, and message formats. The guide details the process of implementing an event-driven API using Node.js and AsyncAPI, including setting up an AsyncAPI file, generating application code with the AsyncAPI Generator, and testing the application with MQTT.js. Additionally, Bump.sh is introduced as a tool for documenting and tracking event-driven API changes through an AsyncAPI contract, ensuring effective communication and collaboration among developers. By combining AsyncAPI and Bump.sh, developers can create well-documented, high-quality event-driven APIs that are easy to manage and understand.