So the idea is, money in, data out.  I think that's a great starting point.

And you can have money=0

So in the base case it's just an API, right?

Then there is the discovery.  That seems to be a separate part.  How to find a machine.

Then there is the payment.  ie on-chain, mint, lightning, cashu

Then there is the need to make it fast, ie sub 400ms.

I think make it into small logical micro sections that can be simply implmented and less monolitic.