On an iPhone, when we log in to an app, we click a login button, and a website pops up to verify our credentials. Once verified, the website then redirects back to the app, and you are logged in. This familiar Single Sign-On (SSO) pattern is frequently referred to as the redirect flow for authentication. The use of a web browser for auth in this example is considered a “Best Current Practice” for security and usability reasons.
This is a companion discussion topic for the original entry at https://developer.okta.com/blog/2022/01/13/mobile-sso