The article provides a detailed guide on how to add a custom OAuth2/OpenID Connect provider to Strapi v4, an open-source headless CMS based on Node.js. It explains the differences between OAuth2, which handles authorization, and OpenID Connect, which manages authentication, highlighting their integration within Strapi to retrieve user information and create internal users. The process involves using dependencies like Grant and Purest for configuring and managing API calls, checking if the desired providers exist within configuration files, and applying necessary patches to integrate a new provider successfully. Additionally, it covers the internal handling of users and permissions through Strapi's plugins, outlining specific file edits and commands needed to enable a custom login provider, with reference to a demo repository for practical implementation. The article suggests consulting further resources like the OAuth2 and OpenID Connect: The Professional Guide ebook for deeper understanding.