Overview

Think of Amazon API Gateway as a receptionist for your web services. Just like a receptionist manages incoming visitors and directs them to the right department, API Gateway manages incoming API requests and routes them to the right backend services.

It sits between your users (clients) and your backend services, handling all the complex tasks involved in accepting and processing up to hundreds of thousands of concurrent API calls. This includes traffic management, security, monitoring, and version control.

API Gateway can connect to various backend services, including AWS Lambda functions, EC2 instances, or any publicly accessible web service. It handles all the heavy lifting of request and response processing, so developers can focus on their application logic rather than infrastructure.

One of its key benefits is that you only pay for the API calls you receive, making it cost-effective for both small applications and large-scale systems. It also provides tools for API versioning, different deployment stages (like development, testing, and production), and API documentation.

Example uses

Mobile Backend: A mobile app can use API Gateway to securely access backend services, like retrieving user data from a database or processing payments, without exposing the backend directly to the internet.
Microservices Architecture: Companies can use API Gateway to create a unified API interface that connects to multiple microservices, making it easier for clients to interact with their system through a single entry point.
Serverless Applications: When combined with AWS Lambda, API Gateway can create fully serverless applications where API endpoints trigger specific Lambda functions to process requests and return responses.
Third-party API Management: Organizations can use API Gateway to expose their services to partners or customers, complete with usage plans, API keys, and monitoring capabilities.

Integration with other AWS services

API Gateway works seamlessly with many AWS services:

AWS Lambda: The most common integration, allowing you to create serverless APIs where each endpoint triggers a specific Lambda function.
Amazon S3: Can be used to serve static content or store API responses for caching.
Amazon Cognito: Provides user authentication and authorization for your APIs.
AWS IAM: Enables fine-grained access control to your APIs.
Amazon CloudWatch: Monitors API usage, latency, and errors, providing detailed metrics and logs.