I have a big project in mind

And how would i do that?

Also read this, I think this can help...

Check the libraries! There is a new one called MQTT.

What exactly does this library does?
(Sorry for the questions, its just idk anything)

its a really fast way to transmit data.

Its just like Netsblox?

netsblox uses rtc (i think) but mqtt is an equivalent

Ok! And next step is the server? Where to host it?

You dont need one with the library; its already provided.

Is there a tutorial for using this library?

its pretty self explanitory

well, it should be stored as a json string in the server, and we can use the importSprite primitive for sprites and things

You will have security issues.
then to fix the issues you will eventually make your project just a clone of snap

what security issues and why?
i don't get why any would happen or why snap would need to be replaced

a bunch of people drawing on one sandbox

then you will make a lot of sand boxes which just becomes a clone of snap

that doesn't sound like a security issue, and reading over all these posts i don't know what scratchmodification is trying to do, maybe that's the intention.

also you don't need sandboxes, if you wanted one snap server instance per person you would just run more of the program, nothing needs to be sandboxed.

i mean it as white board