While there are as many proprietary authentication methods as there are systems that utilize them, they are largely variations of a few major approaches. In this post, I will go over the four most used in the REST APIs and microservices world.
Authentication vs. Authorization
Before I dive into this, let's define what authentication actually is, and more importantly, what it’s not. As much as authentication drives the modern internet, the topic is often conflated with a closely related term: authorization.