I've been using one called FLOWN. It's not just for engineers, but some community sessions are themed (writing, coding, etc). There is not much chat in these other than sharing your intentions and reflecting on how you did afterwards--the main point is focusing in a video call with other people.
I'm guessing he's looking for a chat room to discuss stuff with like-minded people in between working sessions, perhaps also some form of accountability to reduce the tendency towards distraction and procrastination.