Hello, everyone!
I have programming experience, so I guess it’s a good jump start. I was trying to search the internet for information on a specific topic: making a simple mobile multiplayer game. However, there isn’t much available at all. What problems should I expect?
I’ve found some information about regular multiplayer games, but not specifically for mobile. From your experience, for those who have built the backend, how did you approach it and what tools did you use?
I like to develop the server / client side
Not much available? What did you search for? Possibly you were using a very narrowly defined search. Generally speaking „simple“ and „mobile“ make the search too narrow, there is plenty of tutorials on making „multiplayer games with unity“.
The concepts for making multiplayer games on mobile are the same as for any other platform, only the hardware is limiting in terms of cpu + gpu + memory + screen size, connectivity (only wlan or over the air) and most importantly: input (touch controls).
Thanks , belive me i searched for example threads like this
Im looking for help from someone one that did build such type of game which used by large scale of users .
Typically that will have been made by large teams / a company and they don’t put out tutorials “make a game like ours” for obvious reasons - one being that they wouldn’t want to enable piggybackers riding the wave of success while diminishing theirs, second they’re just too busy managing that game and possibly building the next or in any case, creating business value (tutorials don’t).
It is extremely rare to find such a game with large number of users by a solo dev. This cute 2D top-down farming game comes to mind (I can never remember that name) but that wasn’t even for mobile.
What you can find is advice on scaling users if you search specifically for those, but for that you need to acquire domain knowledge. For example, it makes quite the difference whether you use Netcode for GameObjects - which allows for no more than 200 concurrent users, possibly far less but the simulation will be in realtime - or a turn-based game which could easily be implemented with a regular web request and server backend with the usual tech (JS, PHP, SQL, etc) and that scales to possibly any number of users. In this case it becomes more a matter of scaling the number of servers / cloud service (eg AWS).
Since you haven’t mentioned what kind of game you want to make it is practically impossible to give any suggestions. Once you define the design of the game it narrows down the usable and sensible options, and that will make it easier to find suggestions and tutorials. 
Thanks , all this well known .
I wroth , IO game , but with true networking not the fake onces .
Example : paper io
if you want to make commercial game and need help, check also some professionals here:
i’ve seen multiplayer/networking experts offering (paid) help there.
looking for personal expiriance if pusible
Thanks