[SilasX]

>So generate immutable ProductState objects that contain all parts of the domain model that can change over time, and maintain a mapping from SKU to the correct object.

But that just recreates the very problem the author set out to solve, which is that you have to send increasingly huge sub graphs of the database with each order.

I assumed the direction he was going to go was to let the client send the at-the-time data back with each subsequent request for time consistency, but require them to pass a server-provided signature to keep them from making up prices, and saving the server from having to keep a time history of every case.