What is Azure API Management?

 

Introduction to Azure API Management

Azure API Management is a comprehensive solution for managing APIs in a secure, scalable, and reliable manner. It provides a range of features to help developers expose their APIs to external and internal consumers, ensuring seamless integration and management.

Key Components

1. API Gateway: Acts as the entry point for client requests, enforcing security, rate limiting, and request transformations.
2. Management Plane: Manages the API lifecycle, including creation, publishing, monitoring, and analytics.
3. Developer Portal: A self-service portal for API consumers to discover APIs, read documentation, and obtain API keys.
4. Backend Services: The actual services that the APIs expose, which can be hosted on Azure, on-premises, or third-party systems.

Example: Securing an API with OAuth 2.0

Step 1: Register an Application in Microsoft Entra ID

1. Go to the Azure portal and navigate to App registrations.
2. Click on New registration and fill in the required details.
3. Note down the Application (client) ID and Directory (tenant) ID.

Step 2: Expose an API

1. In the registered application, go to Expose an API.
2. Set the Application ID URI and add a scope (e.g., api.read).

Step 3: Configure API Management

1. In your API Management instance, go to the API you want to protect.
2. Add a policy to validate the JWT token. Here’s an example policy:

<inbound>
    <validate-jwt header-name="Authorization" failed-validation-httpcode="401" failed-validation-error-message="Unauthorized. Invalid or expired token." require-explicit-authorization="false">
        <openid-config url="https://login.microsoftonline.com/{tenant-id}/v2.0/.well-known/openid-configuration" />
        <audiences>
            <audience>{application-id-uri}</audience>
        </audiences>
    </validate-jwt>
</inbound>

Replace {tenant-id} and {application-id-uri} with your actual tenant ID and application ID URI.

Step 4: Client Application

1. The client application needs to acquire an OAuth 2.0 token from Microsoft Entra ID.
2. Use this token in the Authorization header when making requests to the API.

Conclusion

Azure API Management simplifies the process of exposing and managing APIs, providing robust security, scalability, and monitoring capabilities. By following the steps above, you can secure your APIs using OAuth 2.0, ensuring that only authenticated and authorized clients can access your services.