How to implement OAuth 2.0 in Node.js

OAuth 2.0 is a critical protocol for managing secure user authentication and authorization across various services and APIs, especially in environments using JavaScript and Node.js. The article explores how to implement an OAuth 2.0 server using the node-oauth2-server module, a framework-agnostic tool that simplifies integration with Node.js applications. Despite not being recently updated, node-oauth2-server remains compatible with the latest Node.js standards, providing a straightforward way to integrate OAuth 2.0 into existing projects. The implementation process includes setting up a Postgres database for user management and token storage, creating endpoints for user registration and login, and securing API endpoints by authorizing users through bearer tokens. The example provided uses the password grant type, but the implementation can be adapted for other grant types. The article further highlights the use of Postman to test the OAuth 2.0 implementation, demonstrating how to register users, log in, and access secure endpoints. By following the outlined steps, developers can gain a foundational understanding of incorporating OAuth 2.0 into their applications, using Express and PostgreSQL to build a scalable and secure authentication system.