The tutorial provides a step-by-step guide on how to build a secure API in Ruby on Rails using JSON Web Tokens (JWTs). It starts by creating a new Rails application and setting up the necessary routes for the API. The tutorial then explains how to create a test user and generate a JWT token, which is used to authenticate requests to the API. The code includes tests to ensure that the authentication process works correctly, and it also covers additional security measures such as verifying the issuer and audience claims in the JWT. Finally, the tutorial provides suggestions for extending the example and integrating with an identity store like FusionAuth.