[megous]

Any node server app will be ~50-100 MiB (because that's roughly the size of node binary + shared deps + some runtime state for your app). If you failed to optimize things correctly, and you're storing and working with lots of data in the node process itself, instead of it serving as a thin intermediary between http service and a database/other backend services, you may get spikes of memory use well above that, but that should be avoided in any case, for multiple reasons.

And most of this 50-100 MiB will be shared if you run multiple node services on the same machine the old way. So you can run 6 node app servers this way, and they'll consume eg. 150MiB of RAM total.

With docker, it's anyone guess how much running 6 node backend apps will consume, because it depends on how many things can be shared in RAM, and usually it will be nothing.