Our organization recently completed a migration of a customer-facing portal from Azure AD B2C to Microsoft Entra ID (formerly Azure AD). The decision was driven by a need for deeper integration with our internal M365 ecosystem and a reassessment of long-term FinOps strategy. This was not a trivial lift-and-shift, and the operational differences are significant.
Key findings from the migration process:
* **Cost Structure Shift:** Moving from B2C's monthly active user (MAU) model to Entra ID's per-user licensing required a detailed analysis of our user base. For our low-frequency portal, the MAU model was initially more favorable. However, consolidating with our existing Entra ID P1 licenses for employees created a net saving by eliminating a separate billing line.
* **Feature Parity is Not Automatic:** Several B2C-specific features, like customizable user flows and identity providers (e.g., social logins), are implemented differently. We had to rebuild the authentication user journey using Entra ID External ID for customers, which offers more granular integration points but less pre-built UI.
* **Administrative Overhead Changed:** B2C operates in a somewhat isolated tenant. Entra ID integration means our customer identities now reside alongside employee identities. This demanded stricter governance and scoping of administrative roles to maintain security boundaries.
The most substantial learning was that this migration is fundamentally an identity architecture redesign, not a simple service swap. The development effort to adapt our application to the Microsoft Identity Platform libraries and the new policy configurations was considerable.
For teams considering a similar move, I recommend a thorough comparison of:
* The total cost of ownership under both models, factoring in license consolidation.
* The development cost of re-implementing authentication journeys.
* The operational model for managing external identities within your primary tenant.
—EK
Your bill is too high.