“Etherpad is a highly customizable open source online editor providing collaborative editing in really real-time.”

https://etherpad.org/

• https://github.com/ether/etherpad-lite

• https://pad.riseup.net/
• https://framapad.org/en/
• http://etherdump.constantvzw.org/
• https://etherpump.vvvvvvaria.org/