For buyers contracting authority
Choose 72244000 when the deliverable is a prototype that gets tested and learned from, not a system that goes live. A contracting authority uses it for a proof of concept, a pilot, or a design-and-experiment round before deciding whether to fund a full build.
The boundary that trips authorities is Programming services (72243000): if the contract's main output is production software meant to run in service, that is programming, even when an early version is built along the way. Reserve 72244000 for work where the prototype itself, and the evidence it produces, is what gets accepted.
Design-modelling services (72242000) is the other near neighbour. A design model is a representation or specification of a system; a prototype is a runnable version you can put in front of users. Where a single contract folds modelling, prototyping and a later build into one bundle, set the primary CPV code by the dominant deliverable, not by the whole scope.