OAuth 2.0: Unlocking the World's Most Popular Authorization Framework

This article provides a clear explanation of the OAuth 2.0 protocol. Using the example of building a code deployment platform, the author illustrates how OAuth 2.0 solves the security issues of sharing user credentials, comparing the advantages and disadvantages of using plain user credentials and Personal Access Tokens (PATs). The article details the three core roles in OAuth 2.0 (Resource Server, Resource Owner, and Authorization Server), and various authorization flows (Authorization Code, Implicit, Client Credentials, Resource Owner Credentials, and Device Code flows), analyzing the security and applicability of each. Key concepts such as access tokens, refresh tokens, scopes, and PKCE are also explored.