What is Collab Mode?
Collab Mode allows more than one person to edit a pen at the same time. Real-time pair programming at its best, since the two people can be anywhere in the world!
Every character you type, every line you select, and every setting you change happens immediately on all of your collaborators screens. And likewise for everything they do.
How many people can collaborate at a time?
Collab Mode is only available to CodePen PRO members. Basic PRO members can collaborate with one other person (two people in a room). Super PRO members can collaborate with up to six people in a room.
What happens if the owner leaves the room?
Every Collab Mode room has an owner. It is the person who owns the Pen that the room was created from. Collab Mode only works if the owner is in the room. If the owner leaves, the room is closed. The collaborators in the room will see a message informing them that the owner has left.
How does chat work?
In each Collab Mode room, there is a live chat area (like Professor Mode). You and your collaborators can start the chat from the "Open Chat" tab at the bottom of the editor.
These chat sessions are saved to that particular Pen, so you can always open the Pen up in Collab Mode again and see the chat history.
Note that comments on your Pen are separated by the type of view you are in. Any given single Pen might have comments on it (from the Details view) Collab comments on it (from Collab Mode) and student comments on it (from Professor Mode).
Are the changes that are made in Collab Mode saved?
Only if the owner of the Pen chooses to save them (only they see a Save button). If you are collaborating and want to save the progress, you can click the Fork button and save a fork of the exact state of the Pen at that time.
What else is Collab Mode good for?
You could use Collab Mode to conduct phone interviews with front end devs. Rather than quiz them about CSS selectors, have them prove they know them by writing code for you live. This is likely a more true measurement of their skill, since most of us can code better than we can talk about it.
Collab Mode also gives you a venue for private tutoring. Perhaps you're a great teacher of Angular.js. You could sell your time privately and connect with students to teach on CodePen.
Collab Mode is also a real time private chat room, so anytime the need for that comes up you'd be covered!
And this is just one of many features you get on CodePen PRO.