A problem JWT can solve:

In our company we have a lot of little REST servers serving some duties. To minimize the chaos I want to have a central authentication and authorization point. If we assume having 20 images running and we look at typical way how authorization works:

there is image A (Authentication), image S (Service) und client C. Client C wants to use the service S

1. client C authenticates and retrieves authorization information from A (or from S which redirects him to A)

2. client C hands out the authorization information to S

3. S needs to check at A if the information is valid (client C could have modified it or generated it)

4. S grants C access

Taking the assumption of having 20 service images, every image would need to get back to A in order to check authorization information. The more services images you have the more load it will put on A. In a JWT use case scenario the same would look like

1. client C authenticates and receives a JWT containing authorization information. The token is signed by A

2. client C hands out JWT to service S

3. S checks the signature of A and knows that the authorization information contained is valid.��

4. S grants C access