Firebase Authentication can be seamlessly integrated and migrated to Amazon Cognito, a secure standards-based Identity Provider. We accomplish this using Cognito’s inbuilt user migration capability. This works by using Lambda to sign in with Firebase Authentication on the user’s behalf the first time they attempt to sign in with Cognito. If the user hasn’t already migrated to Cognito, then upon a successful sign in to Firebase, the user’s credentials are copied to Cognito. Every subsequent sign in will use Cognito directly with the user’s original Firebase Authentication credentials. This avoids requiring users to reset their passwords after migration.