This is a configurable option in nginx. You can have it wait until the entire request is recevied before passing to the upstream (backend) or have it stream as

This is a configurable option in nginx. You can have it wait until the entire request is recevied before passing to the upstream (backend) or have it stream as data arrives. I seem to recall there is still a manageable buffer when streaming too, though it's been a few years since I looked at that in detail.