In this article, the author sets up an API gateway with microservices for an eCommerce enterprise using FusionAuth as the centralized authentication system. The goal is to implement JSON Web Token (JWT) authorization to secure access to the microservices. JWTs are used to verify the identity of users and ensure that only authorized applications can call the microservices. The author demonstrates how to create a JWT, sign it with FusionAuth's default signing key, and use it to authenticate requests to the microservices. The article also covers how to integrate JWT authorization into the API gateway and microservices, including adding an authorization middleware to verify the JWT and extract roles from the token. By implementing JWT authorization, the author achieves a more secure and flexible authentication system for the eCommerce enterprise's API gateway and microservices.