Developing SaaS application with future mobile app release

Hi all.
I intend to write a web-browser based SaaS application using Wappler. In the future, once the app is released, I intend to develop a sister app for mobile.

Is it best to develop in this order?
I am currently assuming the mobile app will/can utilise the core SaaS app APIs. Is this correct?

Any guidance is greatly appreciate as I don’t want to start off on the wrong path and have to rewrite code later down the line. Many thanks in advance.