OAuth 2.0 is the industry-standard authorization framework designed to allow applications to access resources on behalf of users, replacing its predecessor OAuth 1.0 in 2012. It supports various flows suitable for different use cases, such as the authorization code flow for web applications where users are present and the client credentials flow for server-to-server communications without user interaction. The implementation of OAuth 2.0 can be complex due to its interconnected components, with common challenges including misconfigured redirect URIs and incorrect client credentials. Detailed understanding and precise configuration of these components are crucial, as mismatches can lead to errors. Redirect URIs must be pre-registered with the provider and match exactly to prevent security vulnerabilities, while client credentials require secure handling and storage, often using environment variables or secret managers, to prevent unauthorized access. The guide emphasizes careful troubleshooting and familiarity with provider-specific quirks to resolve issues effectively, using tools like Postman or curl for direct testing, and highlights Descope as a potential platform for simplifying identity management integration.