# Operations
<a name="Operations"></a>

The following describes components of Amazon SimpleDB operations.
+ **Subscriber—**Any application, script, or software making a call to the Amazon SimpleDB service.

  The AWS Access Key ID uniquely identifies each subscriber for billing and metering purposes.
+ **Amazon SimpleDB Request—**A single web service API call and its associated data that the subscriber sends to the Amazon SimpleDB service to perform one or more operations.
+ **Amazon SimpleDB Response—**The response and any results returned from the Amazon SimpleDB service to the subscriber after processing the request.

  The AWS Platform handles authentication success and failure; failed requests are not sent to the Amazon SimpleDB service.