the only thing that comes to mind if you're using rtb or a custom bidding ?
The technology should be something that's flexible and where you can rapid prototype and as soon as you're getting money in you should start rewriting it in a language that's best fitted -> and you have data / use cases to actually base a decision on.
This is maybe not helpful but in the end it's what it boils down to most unfounded startups / companies I worked with.
if you have founding it's a complete different topic :) ...
j
stuff ;)