This article builds on the previous part of a series on building a microservice in Golang, creating a simple REST API that uses JWT tokens for authentication. The API is built using the echo project and adds middleware to handle logging, error handling, and JWT token validation. The article also covers implementing a custom error handler and testing the server using a TestMain strategy. Additionally, it discusses interacting with JWT tokens, including generating and parsing them, and touches on the topic of TLS encryption.