Enabling CORS

Cross-Origin Resource Sharing (CORS) is an essential part of serving the API over the same domain or a different hosted domain. The AWS API Gateway provides a feature to enable CORS functionality. Once you have configured an API resource on an API Gateway, you must enable CORS using the API Gateway web console. Enabling CORS over API Gateway resources requires that you set the OPTION method with some response headers, such as the following:

• Access-Control-Allow-Methods
• Access-Control-Allow-Headers
• Access-Control-Allow-Origin

You can take a look at the manual process of configuring CORS in the API Gateway in AWS's official documentation (https://docs.aws.amazon.com/apigateway/latest/developerguide/how-to-cors.html). 

Zappa automates the process of configuring CORS with API Gateway resources by using a setting attribute called cors, as mentioned in the following code snippet:

{
    "dev": {
             ...
             "cors": true/false
             ...
     }
}

Zappa sets the default...