Create a chatroom of your own choice - name it anything!
There are no channel (chatroom) lists, so a secret chatroom name can be used for private discussions. Others can join you either through this app, or by going to https://hack.chat/?your-channel-name on a web browser.
No registration needed! You just enter two things - chatroom name and you nickname. That's all!
GitHub link: https://github.com/RudraNirvan/hack.chat-android