Spring Microservices in Action, Second Edition

appendix B. OAuth2 grant types

After reading chapter 9, you might think that OAuth2 doesn’t seem too complicated. After all, you have an authentication service that checks a user’s credentials and issues a token back to the user. The token can, in turn, be presented every time the user wants to call a service protected by the OAuth2 server.

With the interconnected nature of the web and cloud-based applications, users have come to expect that they can securely share their data and integrate functionality between different applications owned by various services. This presents a unique challenge from a security perspective because you want to integrate across different applications while not forcing users to share their credentials with each application ...