Need some advice on getting started with Flutter


i’m a junior developer, lately i got interested by Stitch. I plan to develop a flutter app with notifications, login and email functionalities.
I want to use the graphQL api of stitch but i wonder if i would still need a server for the notifications and login stuff since there is no SDK for flutter. May i need firebase?

I also heard of realm, can you guide me with the choice of technologies?

Thank you.