The article provides a comprehensive guide on building a simple gRPC server using Node.js and demonstrates how to use Insomnia, a popular API client, to make gRPC requests. It begins by outlining core concepts of gRPC, a protocol for remote procedure calls that allows for cross-platform, language-neutral service connections. The guide details the four types of gRPC service methods: unary, client-streaming, server-streaming, and bidirectional streaming, with practical examples focusing on unary, client-streaming, and server-streaming methods. The project involves creating a gRPC server that supplies real-time data about the International Space Station, utilizing the Open Notify API. The article walks through setting up the server, writing a Protocol Buffer file to define service methods, and implementing the server's functionality with Node.js. It then explains how to use Insomnia to send different types of gRPC requests to the server, highlighting Insomnia's capabilities in API testing, including features like bidirectional streaming, request canceling, and template tags. The article concludes by encouraging further exploration of gRPC and Insomnia's API testing tools, providing a foundation in gRPC server development and Insomnia usage.