Hi,

I'm kinda a beginner in programming video games and I have no experience with doveloping multiplayer games.

Could I program any game in unity, gm studio, game salad...  and make it multiplayer with node.js or something?

32 minutes ago, Elliot Hobbs said:

Could I program any game in unity, gm studio, game salad...  and make it multiplayer with node.js or something?

Yes, although not needed.

Most engines like Unity, GameMaker and Unreal have networking as part of the basic engine. Requiring no external software to create online multiplayer games. If  you do end up using external software it's more of a personal choice than a necessity.

Remember that the problem with making multiplayer games is cost:

Multiplayer services average around +/- $100 a month for a indie game. A inexperienced team making a indie game takes around 3-4 years. If the multiplayer part only takes around 1 year you would need to pay +/- $1 200 just to develop the game.

It's not much but most indie games start with no budget at all.

It's recommended you start by making small 1 player games, to build experience, funding and reputation.

Welcome to game development. 

The problem with multiplayer games is that you need significant distributed systems diagnostics and debugging skills to make it work.

Even experienced programmers often have trouble when the bugs they're chasing only happen when multiple computers are involved. Trying to do the same when you're also trying to learn how to program, and also trying to learn the tools used to program, and also trying to learn how to program games, is unlikely to be successful.

Regarding hosting: While developing, you can host on your own machine. Use port forwarding to let your co-developers get at the server, if you have a distributed team. Test yourself by running multiple clients in smaller windows on the same machine. (Unreal Engine has support for this built-into the IDE!) Once you need to beta test with users, you can rent a server, which will cost $100/month and up for full-size servers with real hardware, which is what you need for high-action FPS games, but less demanding games can probably run on a virtual machine instance of some sort -- Amazon Lightsail, Linode, Dreamhost VPS, etc. Those cost $10 and up. (Maybe even $5 for the smallest.)