The tutorial provides a comprehensive guide on implementing OAuth2 authorization and authentication using the Kong API Gateway OAuth2 plugin, aimed at ensuring secure and seamless resource sharing between services. It begins by explaining the fundamental concepts of authentication and authorization, along with an introduction to Kong Gateway as an open-source API gateway designed to manage traffic and enhance API security. The tutorial proceeds to illustrate the OAuth2 protocol through a relatable example, highlighting key roles such as resource owner, resource server, and client application. It then guides readers through setting up an API server with Node.js Express, positioning it behind the Kong Gateway, and enabling the OAuth2 plugin to handle authorization requests and token management. The tutorial also details the OAuth2 authorization flow, from obtaining authorization codes to exchanging them for access tokens, and emphasizes the importance of scopes for granular control over resource access. By using Kong Gateway, developers can extend their API servers to also function as authorization servers, streamlining the implementation of secure and efficient authorization protocols across interconnected services.