Enhancing User Journeys with Secure API Connectors in Azure AD B2C

Introduction

Today's digital environment makes establishing safe, seamless, and personalized user journeys of paramount importance to those businesses that hold customer engagement and data protection as their top priorities. Organizations can harness Azure AD B2C to create customized user flows and user journeys with API connectors, enabling integration with external data sources for enhanced security measures and greater granularity at every step in the authentication process.

This blog will explore how to implement and leverage API connectors in both user flows and custom policies in Azure AD B2C, showcasing their role in optimizing security, compliance, and user experience.

Why API Connectors are Essential for Modern User Journeys

API connectors in Azure AD B2C allow you to enrich user journeys by integrating external services during authentication. This capability supports scenarios like identity verification, dynamic data enrichment, and conditional access based on real-time data, making API connectors essential for industries requiring adaptive, secure, and personalized user experiences. The secure communication with external APIs at critical stages of the user journey enables Azure AD B2C to go beyond basic identity management and deliver tailored experiences that align with regulatory requirements, security policies, and business goals.

Implementing API Connectors in Azure AD B2C User Flows: Key Steps

To set up an API connector for a user flow in Azure AD B2C, you'll follow several key steps. Here's a breakdown of the process:

Create an Azure Function in Function Apps
• In your Microsoft Entra ID Tenant (not the azure ad b2c tenant), create a new Function App to host your API logic. This function should contain custom logic, such as user attribute validation, external data lookup, or any other custom processing needed during user authentication.
• Configure your function's endpoint URL, noting it for the next steps, and ensure it meets security and authentication requirements compatible with Azure AD B2C.
Set Up the API Connector in Azure AD B2C
• Switch back to the azure ad b2c tenant, and go to API connectors in the Azure AD B2C portal.
• Create a new API connector, input the endpoint URL of the Azure Function you just created, and set the necessary authentication type - basic or certificate, and create a username and password.
Associate the API Connector with a Specific User Flow
• In the Azure AD B2C portal, select the user flow (e.g., sign-up or sign-in) where you want to integrate the API connector.
• Under the API connectors settings for the user flow, add the configured API connector at the specific stage required—either "After federating with an identity provider during sign-up," "Before creating the user in the directory," or "Before including application claims in token (preview)."
• Test the configuration by running the user flow to ensure the API connector works as expected and triggers at the designated stage.

Following these steps allows you to securely integrate custom logic into your user flows, enhancing the authentication process and allowing for real-time data validation and enrichment.

Use Cases for API Connectors in User Flows

In user flows, API connectors can be applied at three key stages:

After Federating with an Identity Provider During Sign-Up

Use this option to perform additional checks after users authenticate with an identity provider (such as Google or Facebook) but before they complete the sign-up process. This stage is helpful for verifying identity attributes with third-party services before registration continues.

Before Creating the User in the Directory

This option allows you to execute API connectors just before user account creation in the Azure AD B2C directory. Common use cases include external identity verification, compliance checks, and enrichment of profile data to ensure that only validated users are registered.

Before Including Application Claims in Token (Preview)

This preview feature allows API connectors to add or modify claims just before they're embedded in the token issued to the application. For example, a benefits portal might use this to fetch a "vacation days" claim from an HR system, enabling personalized access while keeping sensitive data secure. The enriched claims are typically accessible to backend services and are not displayed directly to end-users in a production environment.

Viewing and Testing Claims in Development Environments

In development, there are several ways to view and test claims:

Token Decoding Tools:
Tools like jwt.ms and JWT.io allow you to manually decode tokens to verify that expected claims are present.
Custom Display Files:
Custom code can be added to the application code to display claims directly in the UI for testing purposes, which can help verify configurations during development.
Application Insights and Logging:
In production, Application Insights or backend logs can be configured to track claims, helping developers monitor and debug claims without exposing them to end-users.

Understanding Custom Policies in Azure AD B2C

Custom policies in Azure AD B2C provide the flexibility to define detailed, multi-step authentication and authorization workflows that go beyond the predefined capabilities of user flows. Custom policies are XML configurations that allow for deeper control over the authentication process, supporting scenarios like password management, adaptive multi-factor authentication, account linking, and data residency requirements. For businesses with stringent regulatory and security requirements, custom policies enable precise control over the user journey, meeting specific compliance, user experience, and security needs that standard flows may not cover.

Some of the advanced features businesses can implement by leveraging custom policies include:

1. Passwordless authentication
2. Multi-factor authentication (MFA)
3. User migration and account linking
4. Custom consent and terms of use agreements
5. External identity providers and social logins
6. Localized UI customizations
7. Risk-based conditional access and fraud prevention

These policies are incredibly flexible and can be tailored to fit any complex business logic, making Azure AD B2C suitable for high-security environments with stringent compliance requirements.

Advanced Use Cases for API Connectors in Custom Policies

API connectors can be leveraged in custom policies for a wide range of advanced scenarios, each supporting specific business needs:

Password Management and Security Policies
• Custom Password Requirements: An API connector can validate passwords against custom complexity rules, ensuring they meet industry standards.
• Password Reset Verification: When users request a password reset, API connectors can integrate with third-party identity verification to authenticate the user before allowing the reset.
Enhanced User Experience and Personalization
• User Profile Enrichment: During sign-in, an API connector can fetch personalized user attributes (like department, account status, recent purchases or reward points) to adjust the user experience based on profile data.
• Localized UI adjustments: API connectors can fetch location data to inform UI customization (like language settings), while the actual localization (updating the UI) would need to be implemented within the application.
Custom Terms of Use and Consent Management
• Dynamic Consent: An API connector can validate the user's agreement to updated terms or privacy policies by retrieving consent records from an external database.
• Audit-Compliant Consent Logging: API connectors can log user consent data in a compliance tracking system, providing audit trails for regulatory requirements like GDPR or CCPA.
Passwordless and Multi-Factor Authentication (MFA)
• One-Time Passcode (OTP) and Biometric Verification: During sign in, the API connector can call some external services to authenticate OTPs or biometrics.
• Adaptive MFA: Based on risk analysis, an API connector can enforce MFA only when a user's activity appears to be risky, thus striking a balance between security and convenience. Complex adaptive risk analysis (e.g., continuous monitoring and real-time risk adjustments) require further integration than just API connectors alone.
Account Linking and Migration
• Linking Social and Enterprise Accounts: Linking social and enterprise accounts typically requires session continuity or more persistent user data management, which is best suited for REST APIs. API connectors can assist but may not fully manage the linking workflow.
• User Migration: API connectors can retrieve individual user attributes from a legacy system during onboarding, incorporating legacy data into the Azure AD B2C profile to ensure a smooth transition for users as they sign up in the new system.
Integration with External Identity Providers
• Custom Identity Verification: An API connector can confirm user details through a third-party identity provider, adding an extra layer of validation.
Data Residency and Privacy
• Region-Specific Data Storage: API connectors can be set up such that user data is routed into different storage silos based on the location, but actual data residency controls are usually handled within data storage policies, not through API connectors directly.
Continuous Integration and Deployment (CI/CD) and Testing
• Automated Testing and Validation: While API connectors can be tested within a CI/CD pipeline, their purpose in CI/CD is limited to validating the logic within the API. API connectors don't inherently enforce compliance across all deployments; they're simply validated as functional or compliant when triggered during the pipeline.

Each of these categories can contain multiple scenarios, tailored to meet industry-specific requirements, regulatory standards, and user experience goals. Custom policies in Azure AD B2C provide unparalleled flexibility, making them an ideal solution for enterprises needing adaptive identity management.

Best Practices for Implementing API Connectors

Security and Compliance: Use secure authentication methods (like OAuth 2.0 or mutual TLS) to protect API connectors, especially when handling sensitive user data.

Performance Monitoring: Use Azure Monitor and Application Insights to monitor API connector performance and troubleshoot issues, ensuring they operate efficiently without impacting the user experience.

Role-Based Access Control: Implement role-based claims in your tokens to enforce fine-grained access control, particularly in multi-level authentication and authorization scenarios.

Choosing between API Connectors and REST APIs in Azure AD B2C

In Azure AD B2C, both API connectors and custom REST APIs enable integration with external systems to enhance user journeys and authentication processes. While API connectors are lightweight and ideal for single-purpose, event-driven tasks, custom REST APIs offer greater flexibility for complex, multi-step workflows that require session continuity, advanced error handling, or custom access control. Choosing between API connectors and REST APIs often depends on the complexity of the workflow and the need for persistent session management across interactions. The following table highlights key differences to help determine when to use each option.

Conclusion

API connectors in Azure AD B2C offer immense potential for creating secure, personalized, and compliant user journeys. While user flows provide essential integrations, custom policies unlock advanced capabilities, enabling you to meet complex business requirements and build adaptive identity solutions. By harnessing API connectors with custom policies, organizations can ensure that each stage of the user journey aligns with security standards and enhances the overall user experience.

If you're ready to implement or optimize API connectors in Azure AD B2C, ZappSec's expert team can guide you through the process, ensuring seamless integration and strong security. Contact us today to explore how API connectors and custom policies can elevate your identity management solutions.