Web-based there isn’t AFAIK a good one for code editing. There used to be a good one based on Etherpad, but it has been abandoned some years ago.
I personally like: https://www.saros-project.org/
Not web-based, but all you need is a somewhat modern XMPP server to do the communication, no other server side component required.
Red Hat hosts a public service for Eclipse Che.
https://www.eclipse.org/che/docs/che-7/hosted-che/hosted-che/
Web-based there isn’t AFAIK a good one for code editing. There used to be a good one based on Etherpad, but it has been abandoned some years ago.
I personally like: https://www.saros-project.org/ Not web-based, but all you need is a somewhat modern XMPP server to do the communication, no other server side component required.
CryptPad or Etherpad
You write code on those?
For quick collaborative coding, yes
HedgeDoc is really great, though it is markdown. OnlyOffice and Collabora also work pretty well.
I think it was collabora which can not do multiple cursors