Microservices is a great architecture for modern applications that need to be scalable and resilient to failures in order to be able to support millions of transactions.
In order to understand why the microservice architecture can be better than monolithic, it is needed to understand the drawbacks of monolithic applications.
In this second tutorial of IdentityServer4, we are going to understand the different Flows that OpenID has. This is important because depending on the necessities of the application we need to use a specific flow. After that, we are going to configure the IdentityServer4 application to work with the hybrid flow (although you can change it to the Implicit flow and it will work). Then we are going to build a client application that can call the IdentityServer to authenticate itself to get an Id_token and an Access_token.
David Mata blog 