Hello!
In this direction haxe tooling is fragmented and often not completed.
If you want to write such kind of applications painless I advice you using node.js infrastructure. Of course you can do it with haxe.
Frontend: react.js for browser and react native for mobiles.
There is an awesome instrument for generating haxe externs for npm libs.
You can find react js externs here GitHub - kLabz/haxe-react: Haxe-React #next: preparing for 2.0.0 .
There remarkable video about using haxe with react https://youtu.be/sUlIgZ1hHR4
There is also amazing ui lib for building web and mobile interfaces with react.js/react native layers beneath