Web-based Training Application Updates

I have an existing web-based training application that needs some features added to it. We are initially looking to add SMS messaging to provide notifications to users when events are triggered. We are looking at incorporating Twilio for this. Being familiar with integrating this product into exiting web applications is a pre-requisite.

This is a legacy site and our original developer was inexperienced and we are cleaning up code as we go. We are looking for an experienced developer to advise and provide insight.