Conditionally Routing Service Requests

I currently use HAProxy to route requests to a production environment (the default) or a development or testing environment (based on secret cookies). This works well, but maintaining the routing rules is a bit of a chore and frankly the HAProxy configuration is cryptic at best.

Imagine a developer working on a single endpoint. They have their IDE and debugger set up on their workstation and the endpoint is listening for requests. They have a VPN providing a shared network between the production server and their workstation BTW. Ideally, they could go to XXX and change YYY so that a secret cookie would route the service endpoint to their workstation without disturbing anything else, and only for them. The rest of the application would continue to work ‘as-is’ using the production endpoints for everything else.

I am considering using DreamFactory and suspect that it can simplify this aspect of my operations. But how? What are XXX and YYY?

Thanks in advance,