Microsoft Entra External ID is Microsoft's cloud-based CIAM service for customer-facing applications. It provides an external tenant customer directory, customizable authentication journeys, social and enterprise identity federation, multi-factor authentication, and integration with the Microsoft identity platform. It removes the need to operate an identity store, but it bills per monthly active user (MAU) above a free allowance of 50,000 MAU on the Basic tier, meters SMS phone verification sep...