Not OP, but… concurrency is not the same as parallelism. This is an important hair to split: https://stackoverflow.com/a/24684037/1026671 https://stackoverflow

Not OP, but… concurrency is not the same as parallelism. This is an important hair to split: https://stackoverflow.com/a/24684037/1026671 https://stackoverflow.com/a/24684037/1026671 "Concurrency" doesn't warrant scare quotes even when describing a single threaded program. It's true that Node.js allows one task to block many others, but that's an implementation detail of Node.js, not a guaranteed result which necessarily applies to any program using only one OS thread. Other programs suffer from analogous starvation/deadlock/livelock/priority inversion problems, but those would be implementation details too, not guaranteed results from using multiple OS threads.