receiving error: Execution failed due to configuration error: Malformed Lambda proxy response

Receiving Error: Execution Failed Due to Configuration Error: Malformed Lambda Proxy Response

If you are working with AWS Lambda and encountering the error message “Execution failed due to configuration error: Malformed Lambda proxy response,” you’re not alone. This error typically occurs when the response returned by your Lambda function does not adhere to the required format for API Gateway proxy integration.

Fortunately, there are a few solutions to this problem. Let’s explore them one by one.

Solution 1: Correctly Formatting the Lambda Proxy Response

The first solution involves ensuring that your Lambda function returns a properly formatted response. The response should include the following properties:

exports.handler = async (event) => {
  const response = {
    statusCode: 200,
    headers: {
      "Content-Type": "application/json"
    },
    body: JSON.stringify({ message: "Hello, world!" })
  };
  
  return response;
};

In this example, we define a Lambda function that returns a JSON response with a “statusCode” of 200, appropriate headers, and a “body” property containing the desired payload.

Solution 2: Enabling Lambda Proxy Integration in API Gateway

If you have already implemented the correct response format in your Lambda function but are still encountering the error, the issue may lie in your API Gateway configuration. To resolve this, you need to enable Lambda proxy integration for your API Gateway endpoint.

Here are the steps to enable Lambda proxy integration:

1. Open the API Gateway console.
2. Select your API.
3. Navigate to the desired resource and method.
4. Under “Integration type,” select “Lambda Function.”
5. Check the “Use Lambda Proxy integration” box.
6. Save your changes.

By enabling Lambda proxy integration, API Gateway will pass the entire request and response objects to your Lambda function, allowing you to handle them directly.

Solution 3: Verifying Request and Response Mapping Templates

If the previous solutions did not resolve the issue, it’s worth checking your request and response mapping templates in API Gateway. These templates define how API Gateway transforms the request and response objects before passing them to your Lambda function.

Ensure that your request and response mapping templates are correctly configured and aligned with the expected format of your Lambda function.

Conclusion

The “Execution failed due to configuration error: Malformed Lambda proxy response” error can be frustrating, but with the solutions outlined above, you should be able to resolve it. Remember to check the formatting of your Lambda proxy response, enable Lambda proxy integration in API Gateway, and verify your request and response mapping templates.

By following these steps, you’ll be on your way to successfully handling API Gateway proxy integrations with AWS Lambda.