Scaling a PHP web app, using EasyXDM

Hello,

I am using easyXDM to send data back and forth from a content management system (wp), hosted on a customer’s server to my company server for processing. It is then sent back to the customer.

There are two files on the company server that do the processing, communicating via JSON. My question is that as this product scales, there is potential for these files to get hit pretty hard.

Are there things I should be aware of, outside of getting good hosting? I will get a dedicated server as I grow. Would it smart, for example to host the files that see the traffic on multiple servers, in case on goes down. all of my customers will not be affected?

I have built a few applications, but have never tried something like this before. Any insight is appreciated.