Matrix
/dev/hack operates a Matrix homeserver and there is an ongoing effort to move most discussion there.
You can create and use their matrix account by going to matrix.devhack.net in a browser or configuring any matrix client with homeserver matrix.devhack.net. You will be asked to sign in with your IDP account.
Non-members and members who do not wish to use the devhack homeserver are welcome to join the space at #devhack:devhack.net and the main room at #general:devhack.net from their own homeserver.