Introduction to API Gateway
Understand the role of API Gateway in a serverless architecture, its key features, and how it acts as a front door for your applications.
Introduction to API Gateway is a free Serverless Backend with AWS Lambda & API Gateway lesson on CoddyKit — lesson 1 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Serverless Backend with AWS Lambda & API Gateway learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.
Intro to API Gateway
Welcome to your journey into AWS API Gateway! In serverless architectures, services like AWS Lambda handle your application's logic, but how do users access them?
API Gateway acts as the front door for your applications, handling all incoming API requests before they reach your backend services.
Your Serverless Front Door
Think of API Gateway as a highly scalable, fully managed service that sits between your users and your backend. It's like a traffic controller for your APIs.
- It receives HTTP requests from clients (web browsers, mobile apps).
- It routes these requests to the correct backend service.
- It returns the responses from your backend to the client.
Why Use API Gateway?
API Gateway isn't just a router; it provides many features that simplify building robust APIs:
- Scalability: Handles millions of API calls automatically.
- Security: Protects your backend services.
- Flexibility: Connects to various AWS services (Lambda, EC2, etc.).
- Monitoring: Integrates with CloudWatch for logging and metrics.
How it Routes Requests
When a client sends a request to your API Gateway endpoint, API Gateway uses configured routes to determine where to send it. For example, a request to /users might go to a Lambda function, while /products goes to another.
This routing is based on the HTTP method (GET, POST, PUT, DELETE) and the path of the URL.
Built-in Security Features
Security is paramount, and API Gateway offers several ways to protect your APIs:
- IAM Roles: Control who can invoke your API using AWS Identity and Access Management.
- Custom Authorizers: Use Lambda functions to implement custom authentication and authorization logic.
- CORS: Manage cross-origin resource sharing to allow specific domains to access your API.
Traffic Management
API Gateway helps you manage traffic efficiently:
- Throttling: Prevents your backend from being overwhelmed by too many requests. You can set limits per second.
- Caching: Stores responses from your backend to reduce latency and load on your services for frequently accessed data.
Transforming Requests
Sometimes, your backend service expects a different input format than what clients send. API Gateway can transform requests and responses using mapping templates.
These templates allow you to modify headers, query parameters, and body content before sending them to your backend, or before sending the backend's response back to the client.
Connecting to Lambda Functions
One of the most common uses for API Gateway in serverless is integrating with AWS Lambda. API Gateway acts as the trigger for your Lambda functions.
When an API Gateway endpoint is invoked, it passes the request details (headers, body, query params) as an event object to your Lambda function.
Lambda Handler Example
Here's a simple Python Lambda function that API Gateway could trigger. It returns a basic message as an API response.
API Gateway handles the HTTP request, invokes this function, and then takes the function's return value to construct an HTTP response for the client.
import json
def lambda_handler(event, context):
# This function is triggered by API Gateway
# The 'event' object contains details about the incoming HTTP request
print("Received an API Gateway request!")
return {
'statusCode': 200,
'headers': {
'Content-Type': 'application/json'
},
'body': json.dumps({'message': 'Hello from Lambda via API Gateway!'})
}Quick Check
Which of the following best describes the primary role of AWS API Gateway in a serverless architecture?
Recap & Next Steps
You've learned that AWS API Gateway is a crucial component in serverless architectures, acting as a scalable and secure 'front door' for your applications.
- It routes requests to backend services like Lambda.
- It provides features like security, traffic management, and request transformation.
Next, we'll dive deeper into the different types of APIs you can create with API Gateway: HTTP APIs vs. REST APIs.
Frequently asked questions
Is the “Introduction to API Gateway” lesson free?
Yes — the full text of “Introduction to API Gateway” is free to read here on the web, and the Serverless Backend with AWS Lambda & API Gateway course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Serverless Backend with AWS Lambda & API Gateway course, upgrade to CoddyKit PRO.
What will I learn in “Introduction to API Gateway”?
Understand the role of API Gateway in a serverless architecture, its key features, and how it acts as a front door for your applications. You practise Serverless Backend with AWS Lambda & API Gateway with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start Serverless Backend with AWS Lambda & API Gateway?
No prior experience is required. Serverless Backend with AWS Lambda & API Gateway on CoddyKit is structured for beginners through advanced learners; this is — lesson 1 of 4, so you can start here or from the beginning and move at your own pace.
How long does the “Introduction to API Gateway” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this Serverless Backend with AWS Lambda & API Gateway lesson?
Yes. Every Serverless Backend with AWS Lambda & API Gateway lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- Introduction to API Gateway
- HTTP API vs. REST API
- Integrating Lambda with API Gateway
- Request and Response Mapping in API Gateway