Best way to send http requests in parallel in python?

Sends 150 requests to BNet? Is it a website or mobile app, and is it doing that every time someone requests data/every second/every minute/every hour/something else?

Well, i would recommend asking this question in a more proper forum like StackOverFlow or something like that. I say this not because noone here could help you, but, because this forum is normally use to talk about things related to the API that Bungie provides, and not about programming itself. The only thing i would say is, check what you are requesting, see if there anything that you actually don't need to request, and get ride of it, after that, check what request actually need to be done synchronous, and from the remaining request send them to a threadpool or what ever is the equivalent of that in Python.