One of the powers of Zimbra is the ability to be extended with custom functionality. The Zimbra front-end can be extended with JavaScript Zimlets and the back-end can be extended with Java extensions.
For the best experience with Hoppscotch, I recommend first converting your WSDL to a Postman Collection, then importing that collection into Hoppscotch. I’ve tested Hoppscotch’s specs, but they didn’t ...