@Suiseiseki @lxo @strypey

Well, the computation of ordering (creating and transmitting orders) would just be front-end aka client-side code, wouldn't it? Typically HTML, CSS, and JS sent to the customer's browser.

This code that runs in the customer's browser will then send data to the server, and the server will do some computation that doesn't concern the customer (receiving and processing orders).

Let's assume the same server application both contains the front-end code that will be sent to the customer's browser, and the back-end code that will process the orders received from the front-end code. I don't think this entire application needs to be AGPL. The only important thing is that the front-end code sent to the customer's browser is under a free license. The customer would then be free to reverse-engineer the ordering protocol (by reading the front-end source code) and build their own client application, if they wish to do so.

I think the only reason to release such an application under the AGPL would be to prevent corporations from exploiting the work of free software developers by massively profiting from a privately improved version of the application without giving anything at all back to the community that created the original version. Indeed, I think that's the main reason the AGPL exists. It's not about preventing companies from running their proprietary code on devices you own, because the plain GPL already does that.