The PivotGrid can communicate with a Web API service. The quantity of aggregated data is irrelevant when aggregation is performed on the server. For example, the UI component works with a million aggregated records in this demo.
To configure access to a Web API service from the client, use the createStore method, which is part of the DevExtreme.AspNet.Data extension. This extension also allows you to configure server-side data processing for DevExtreme UI components.
You should also set the remoteOperations property to true to notify the PivotGrid that data is aggregated on the server.