Once you know what you want to test, you will need to set up your application somewhere to be able to validate it and potentially optimize it.
It may sound obvious but, here, you have to be very strict on that point and benchmark your application in an environment comparable to your final environment. What does it mean? The same machine, same network setup, same load balancing strategy, same backends/databases, and so on.
Any part of the setup must match where you will run. Otherwise, when deploying in production, you may be surprised by some unexpected factors you should have seen coming and evaluated far before this final deployment. The best case is that the application is not functional, which is generally identified ...
