In life, there are many problems posed to the software industry . But most of the software that we create has a security and decentralization mechanism and user management. So what can keycloak do in the above problems? Add Authentication and Authorization to your system. Add UserManagerment to your system. Add Single-Sign-on and Single-Sign-out to your system. Add Permission(Role-User) to your system. Can be used for most types of software deployment models(microservice-monolithic) For ease of visualization I drew it with MONOLITHIC before the keycloak After: So what happens when we use the MICROSERVICE ? The remaining problem is just how to learn and implement them. Stay tuned in the following section !! Tks ALL.