[verdverm]

I doubt firebase or the others listed here (https://meliorgames.com/game-development/back-end-solutions-...) would work for a real-time game, where we are talking tick level logic on the server side. It really depends on what you mean by "real-time game"

I've liked Dapper Dino's videos for learning about these things. Looks like he's started an updated version: https://www.youtube.com/watch?v=eymqAMmnqPg