At least a few years ago it was an actual IRC server and has been since justin.tv. I don’t believe they’ve changed it, as irc clients and bots have continued working with no IRC related changes. (I don’t think they’d invest in providing an IRC gateway; it’d be easier to just abandon it)

An article from late 2015 indicates that IRC is nothing more than an API interface and not their underlying system.

https://blog.twitch.tv/en/2015/12/18/twitch-engineering-an-i...

I can confirm this. Context: part of the engineering team that worked on the chat infrastructure around this time period.

The history is basically:

- v1: IRC API to process scoped servers (Python backend, haxe front end)

- kept API as we migrated backed to go (via a terrible course through nodejs); this version allowed all participants to be in a room together (ie cross process servers).

- once most of background was on go we migrated the front end (can’t remember to what)

- backend then got revved a lot (a specialized team was convened to work on chat infrastructure full time)

I left in 2017, no idea what has happened since.

I thought IRC was just an API interface to begin with? https://datatracker.ietf.org/doc/html/rfc2812

Huh, cool. Not sure when it changed but https://techcrunch.com/2007/05/22/justin-tv-network-launches... is a source for justintv using IRC

I suppose we could dig into that twitch source code leak to confirm