My random thoughts as a dev and SaaS runner.

This seems both too hard and too complex to use for a non-programmer, and not worth enough to a programmer.

As a programmer, It's a lot of work to learn a new API. So learning something to rapid prototype that I have no control over? Why? I can throw up a Django prototype in a day that is going to cover my growing for a lot longer than an endpoint builder.

Just things to keep in mind, not to poop on your plan. It might be a really good plan. If you are serious about it throw up a marketing page and get signups to see if you can get traction.