In Firebase, we can also integrate your own auth systems with Firebase Authentication to give users access to data without forcing them to create an account using third-party APIs of your existing systems. Firebase also allows for anonymous auth sessions, which are typically used to save small amounts of data while waiting for a client to authenticate with a permanent auth method. We can configure this anonymous session with last days, weeks, months, or even years until the user logs in with a permanent login method or clears their browser cache. For example, a shopping cart application can create an anonymous auth session for every user who adds something to their cart while doing a shopping. The shopping cart app will prompt the user to create an account for checkout; at that point, the cart will be persisted to the new user's account, and the anonymous session will be destroyed.