You may have to elaborate further before anyone can help. Like, what is "WS"? WorkSpace?
Where does Postman come into play?
Etc.
Without knowing your situation, I will make some assumptions.
-if your app is running on Google's servers, you are very restricted in what you can do
-if you can get it running locally, like in VSCode, you can try pushing it to Apps script using CLASP.
-- it may not work still, because Google will remove any content it doesn't like
-if your app is Node-based or running in the browser, then you should be able to do what you want because the code is running in the browser, not on Google's servers
--if you create an Apps script web app, it should work too since that will run in the browser and not on the server
--with a web app, you can use JS and not worry about apps script restrictions
This video shows much of what I am referring to, very good for showing local Dev, CLASP, and even using React in Apps script:
https://youtu.be/aq2B02DuCs0