Okta OAuth 2.0 Server is an educational resource and implementation guide for OAuth 2.0 protocol. The resource provides comprehensive documentation and guides for understanding and implementing OAuth 2.0 clients and servers. The content includes OAuth 2.0 Simplified, a guide focused on writing OAuth clients that covers roles (applications, APIs, and users), creating applications, authorization flows for obtaining access tokens, and making authenticated requests. It addresses different application types including web server apps, single-page apps, and mobile apps, along with differences from OAuth 1.0. The resource also features OAuth 2.0 Servers, a guide for building OAuth 2.0 servers that includes implementation details beyond the standard specification. Additional resources include links to client and server libraries in multiple programming languages, books on OAuth 2.0, and consulting services. The guides cover authentication and signatures, user experience and alternative authorization flows, and performance considerations at scale. The resource serves as a starting point for developers and organizations looking to implement OAuth 2.0 authentication and authorization in their applications.