The Relay project provides a service that relays HTTP requests (including WebSockets) to a different service. The most common use is to relay requests from a hostname in one domain to a service in a different domain.
For example, you could run an instance of Relay at design-tool.your-domain.com and configured it to relay requests to a third party service like design-tool.com.
Relay gives you more control and monitoring possibilities over network traffic from your users' browsers that would normally go directly to a third party service.
To get started, check out the Running Relay document.
This project is covered by the MIT License. See LICENSE for details.