Pulse Pro is now officially deprecated, and it is being replaced by the new Pulse for Mac app currently available in TestFlight for testing: https://testflight.apple.com/join/1jcanE3q. It was completely redesigned and has a ton of new features, including response mocking and many more.

Pulse for Mac supports earlier Pulse versions, but version 4.x is required to use the new features

Discussions thread for Pulse 4.0: kean/Pulse#187