PATTERN

API Gateway

Share on:
architectural integration microservices

The API Gateway pattern provides a single entry point for all clients accessing a set of backend services. It sits in front of these services, abstracting their complexity and providing features like request routing, composition, transformation, and authentication. This simplifies client development, improves security, and enables easier evolution of the backend services without impacting clients.

Essentially, the API Gateway decouples the client from the internal microservice architecture. It handles tasks like protocol translation (e.g., REST to gRPC), data aggregation from multiple services, and rate limiting. It’s a central point of control for API management and can also offload concerns like SSL termination and caching.

Usage

The API Gateway pattern is commonly used in the following scenarios:

  • Microservices Architectures: It’s essential for managing external access to a distributed system of microservices, shielding clients from the intricacies of service discovery and internal communication.
  • Mobile Backends: Mobile apps often benefit from reduced network requests and tailored data formats provided by an API Gateway.
  • Web Applications with Multiple Backends: When a web application relies on various backend systems (legacy systems, third-party APIs, modern microservices), an API Gateway can consolidate access and simplify integration.
  • Evolving Backends: Allows changes to backend services without requiring updates to clients. The gateway handles the transformation and routing changes.
  • Security and Monitoring: Provides a central point to enforce security policies (authentication, authorization) and monitor API usage.

Examples

  • Netflix: Netflix’s architecture extensively utilizes API Gateways (Zuul, now replaced by newer solutions) to handle over 3 billion device requests per day. The gateway routes requests to different underlying microservices responsible for various features like user authentication, recommendation engines, and video streaming. It abstracts the complexities of the backend, enabling better scalability and resilience.

  • AWS API Gateway: Amazon Web Services provides a fully managed API Gateway service. Developers can create, publish, maintain, monitor, and secure APIs at any scale. It integrates seamlessly with other AWS services like Lambda, EC2, and DynamoDB, allowing for the creation of serverless backends and hybrid architectures. Features include request validation, transformation, authorization, and caching.

  • Kong: Kong is a popular open-source API gateway built on Nginx. It’s often used in cloud-native and microservices environments due to its extensibility via plugins for features like authentication, traffic control, and analytics. Kong provides a declarative configuration and supports a wide range of protocols and authentication methods.

Samples