OAuth2 Server for Node.js

oauth2-server is a complete, framework-agnostic, and well-tested module for implementing an OAuth2 Authorization Server in Node.js. It adheres to RFC 6749 (OAuth 2.0 Authorization Framework) and RFC 6750 (Bearer Token Usage), providing the core logic for handling various OAuth 2.0 grant types including `authorization_code`, `client_credentials`, `refresh_token`, and `password` grants, as well as support for custom extension grants and scopes. The library is currently at version 3.1.1 and is under active maintenance, with recent releases focusing on bug fixes and dependency updates after a period of hiatus. It distinguishes itself by offering a robust, compliant foundation that can be integrated with any Node.js HTTP framework (like Express or Koa via official wrappers), supporting promises, Node-style callbacks, and async/await for model interactions. It doesn't dictate a specific storage mechanism, allowing developers to plug in their preferred database (e.g., PostgreSQL, MongoDB, Redis).