Azure API Management

Azure API Management (APIM) is a fully managed service for publishing, securing, transforming, and monitoring APIs. In a serverless architecture, APIM sits in front of your Azure Functions, Logic Apps, and other backend services, providing a unified API gateway with security policies, rate limiting, caching, and a developer portal.

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Why API Management?

Without an API gateway, each backend service exposes its own endpoint with its own authentication, rate limiting, and documentation. This leads to:

• Inconsistent security across services
• No centralised monitoring of API usage
• Duplicated cross-cutting concerns (authentication, CORS, caching)
• No developer experience — consumers must discover and learn each API individually
• Difficulty versioning APIs without breaking clients

APIM solves these problems by providing a single entry point that applies consistent policies to all backend APIs.

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Architecture

APIM consists of three main components:

API Gateway

The runtime component that processes API calls:

• Receives incoming requests
• Applies inbound policies (authentication, rate limiting, transformation)
• Routes to the backend service
• Applies outbound policies (response transformation, caching)
• Returns the response to the caller

Management Plane

The administrative interface for configuring APIs: