If caching is not enabled and throttling limits have not been applied, then all requests will pass through to your backend service until the account level throttling limits are reached. If throttling limits are in place, then Amazon API Gateway will shed the necessary amount of requests and send only the defined limit to your back-end service. If a cache is configured, then Amazon API Gateway will return a cached response for duplicate requests for a customizable time, but only if under configured throttling limits. This balance between the backend and client ensures optimal performance of the APIs for the applications that it supports. Requests that are throttled will be automatically retried by the client-side SDKs generated by Amazon API Gateway. By default, Amazon API Gateway does not set any cache on your API methods.