As companies increasingly adopt cloud-native infrastructures, many are choosing to structure their applications using microservices, where each server is dedicated to a single feature, such as billing or user interaction. This architecture requires careful planning of communication between services, often facilitated by APIs using protocols like gRPC, GraphQL, or REST, with REST being the most widely used due to its compatibility with web browsers. The text outlines a process for building and testing a REST API using Node.js and the open-source API client, Insomnia, focusing on fetching and manipulating data while implementing various authentication strategies. It emphasizes the importance of having the latest versions of Insomnia, Node.js, and npm to effectively follow the guide.