How to Use Microsoft 365 MFA in a Third-Party Mobile App
Question details
An organization needs to implement Microsoft 365 multifactor authentication (MFA) within a third-party or internally developed mobile application.
- Product
- Microsoft 365 / Entra ID
- Device & OS
- not provided
- Scenario
- Integrating Microsoft 365 authentication flows into a custom or third-party mobile application.
- Observed behavior
- The mobile application needs to enforce the same Microsoft Entra MFA and Conditional Access policies as standard Microsoft 365 apps.
Ensure you have global administrator or application administrator privileges in your Microsoft Entra ID (formerly Azure AD) tenant to register and configure new applications.
Register and Configure the App in Microsoft Entra ID
Implement the Microsoft identity platform sign-in using OAuth 2.0 and OpenID Connect instead of embedding MFA directly.
To use Microsoft 365 MFA in an external app, you must register the app in Microsoft Entra ID. This delegates authentication to the Microsoft identity platform, allowing users to experience the standard Microsoft sign-in where MFA and Conditional Access policies are seamlessly enforced.
Access the Microsoft Entra admin center using an account with application administrator privileges.
Navigate to 'Identity' > 'Applications' > 'App registrations' and select 'New registration'. Enter your application's name and choose the supported account types.
Under the app registration settings, configure the Redirect URI specifically for your mobile app platform (iOS/macOS or Android) so the identity platform knows where to send the authentication response.
Update your mobile app's code to implement Microsoft identity platform sign-in using OAuth 2.0 and OpenID Connect. Use the Microsoft Authentication Library (MSAL) to handle the secure sign-in experience.
In the Entra admin center, navigate to 'Protection' > 'Conditional Access'. Create a new policy that targets your newly registered mobile app and requires multifactor authentication (MFA) for all users accessing it.
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Frequently Asked Questions
Can I embed the Microsoft MFA prompt natively inside my mobile app's UI?
No, it is highly recommended to use the system web browser or a secure web view to redirect users to the Microsoft sign-in experience. This ensures that Microsoft Entra ID handles the authentication securely using OAuth 2.0 and OpenID Connect.
Do I need Azure AD Premium to enforce MFA on third-party apps?
To use Conditional Access policies that strictly enforce MFA for specific custom applications, your tenant requires Microsoft Entra ID P1 or P2 licenses.
What protocols are supported for integrating Microsoft 365 sign-in into custom apps?
The Microsoft identity platform supports standard protocols such as OAuth 2.0, OpenID Connect, and SAML. For modern mobile applications, OAuth 2.0 and OpenID Connect via the Microsoft Authentication Library (MSAL) are the recommended standards.
