07 Api Gateway Lambda

title: API Gateway and Lambda Integration for Serverless APIs weight: 17 date: 2026-06-28 lastmod: 2026-06-28 description: Integrate API Gateway with Lambda for serverless REST APIs including REST and HTTP APIs, request/response mapping, CORS configuration, and stage deployments. tags: [api-development, serverless]

API Gateway acts as the HTTP front door for Lambda functions, handling request validation, CORS, authentication, throttling, and mapping HTTP requests to Lambda event objects with configurable stages for different environments.

```python
# Lambda handler for API Gateway proxy integration
def lambda_handler(event, context):
    # API Gateway proxy event structure
    method = event["httpMethod"]
    path = event["path"]
    resource = event["resource"]
    headers = event.get("headers", {})
    query = event.get("queryStringParameters", {}) or {}
    path_params = event.get("pathParameters", {}) or {}
    body = json.loads(event.get("body", "{}")) if event.get("body") else {}
    auth_context = event.get("requestContext", {}).get("authorizer", {})

    return {
        "statusCode": 200,
        "headers": {
            "Content-Type": "application/json",
            "Access-Control-Allow-Origin": "*",
            "Access-Control-Allow-Methods": "GET,POST,PUT,DELETE,OPTIONS",
            "Access-Control-Allow-Headers": "Content-Type,Authorization"
        },
        "body": json.dumps({
            "method": method,
            "path": path,
            "params": path_params,
            "query": query,
            "data": body,
            "user": auth_context
        })
    }

What's Next

Now learn about Lambda authorizers in Building Serverless APIs.