QAS Pro Web install location

Hi

We are implementing QAS Pro Web on our website and I was hoping that someone could recommend the best location for this software install.

I have been informed that it can go anywhere - a broad statement - so was wondering what server others had installed it on.  Basically, we have 2 external websites, the API gateway and the production, app, seat and credit server.

I was thinking that the API gateway box would be best but be interested to know what others had done.

Cheers