I was not familiar with web development at that time. My question was about accessing APIs in frontend. All IDEs and Editors can be used for frontend and backend development.
The main point to keep in mind is that your frontend will have its own server and backend will have its own server that will compile and react to changes you made in your code.
Let's say your frontend server serves on localhost with port:8888 and your backend server serves your APIs on localhost with port 8000
By running both server at the same time you can access APIs in your frontend with backend routes like:
'localhost:8000/login'
localhost:8000/user/user_id