Ectochat Chatroom by NoteToServices is free, open-source, and available at https://github.com/cyle/php-redis-chatroom/

Feel free to create your own channel on your own server if you prefer. It does require Redis to be installed.

It uses a Redis Database to store messages into memory for only 10 minutes from the last message sent before it expires. 

If you wish to save your chat, you will need to highlight and save it.

Ectochat chooses a random chat channel for you to ensure absolute privacy. 

Share the channel name which must be entered in the second popup box to share the channel you are in.

Please ensure you do not use generic chatroom names as anyone with the name of the channel could enter the chat and read your conversation 
(if it is within the 10 minutes from the last message sent).

Unlike the P2P chat, which uses browser-to-browser webRTC technology, this chat must hit the server in order to ensure 
a communication network is established, and this method stores data in memory (RAM) rather than a database, 
encrypts the message through a secure communication channel, and the data is never kept on record.