“Wizard of Oz” or “Concierge”
A key insights of good product management is that building is expensive. So, if you’ve got a product idea you need to validate, building that product is the most expensive way to do it.
Luckily, many smart people before us have developed tools and techniques to validate value, viability, and usability without building anything (or building the minimum possible).
One way to validate our ideas with real customers is to (basically) fake it - create something that looks or acts like the product but is really just a person or many people making it work in the background. It doesn’t scale, but it does get you the answers you need quickly.