Does Phoenix have non blocking I/O?

You might find this thread interesting:

TL;DR
The answer is yes.
After reading that thread, since Phoenix uses cowboy and cowboy uses ranch, it basically has non blocking IO.

Thanks

I’m finding this question confusing - as stated it sounds like you want to avoid the “complexity” having to manage non-blocking/asynchronous I/O yourself which, because of the BEAM’s runtime model, Phoenix allows you to do.

Close. all IO conducted by separate processes is non blocking because of how the BEAM itself works, regardless of whether you’re using cowboy or ranch. Ranch handles each HTTP request in its won process, so consequently all the IO done by an HTTP request is non blocking with respect to other processes.

This. All IO on the BEAM is non-blocking, that’s just how it works. Now some interfaces to the IO may serialize on messages, but even that is optional as by default all IO is via messages that you handle however you want. Something like Ranch will spawn a new greenthread (BEAM Process) to handle each IO connection for example, but you could easily just handle many connections in a single greenthread too, or handle each individual message in a process, or distribute it out to multiple computers, or whatever.