connecting-lambda-to-api-gateway

Connecting Lambda to API Gateway Overview Domain expertise for creating Amazon API Gateway REST APIs and connecting them to existing Lambda functions. Covers API creation, resource and method setup, Lambda proxy integration, CORS configuration, security controls, deployment, and testing. Connect a Lambda function to API Gateway To create a REST API and wire it to a Lambda function, follow the procedure exactly. See Lambda to API Gateway connection procedure . The procedure supports configurable authorization types (NONE, AWS_IAM, COGNITO_USER_POOLS, CUSTOM), optional API key requirements, CORS setup, and production security hardening including throttling and access logging. Troubleshooting 502 Bad Gateway The Lambda function must return a proxy-compatible response with statusCode , headers , and a stringified body . See the full procedure for format details. Permission denied invoking Lambda Ensure lambda:InvokeFunction permission was added with the correct API Gateway source ARN. See the full procedure for details. CORS errors in browser Verify enable_cors was set to true, the OPTIONS method was created, and CORS headers are configured in both method and integration responses.