If you create a stage variable to call a Lambda function through your API, you must add the required permissions. Update your Lambda function's resource-based AWS Identity and Access Management (IAM) policy so that it grants invoke permission to the API Gateway

API calls can't exceed the maximum allowed API request rate per account and per Region. Implement error retries and exponential backoffs to fix the error

When setting the Lambda function as the value of a stage variable, use the function's ARN and not the function alias for setting up the value

If you create a stage variable to call a function through your API, you must add the required permissions. Create an IAM role that your Lambda function can assume when invoking the respective AWS resources