Hey, guys at epic! 
I have a great idea! What if you could right click on a project “open for public / open for friends”
Which means: Friends can open the game and “beta-test” it for you. Give feedback etc. Or just try it for the fun of it!
Something that would be insanly great is a function that says: Join project
What this would do is to let someone join the project, move objects around in the level designer, change blueprint - create together!
Please put this in UE4 guys! 
Yep! I think so as well ^^
One other thing is to only allow the original creator to accept changes made as otherwise some people could completely destroy other people’s projects. So this could work where a person can beta-test it and if they want to make blueprint/code/level design changes they can do it but for it to take effect the original maker accepts it.
Just a thought.
Yeah ofcourse! They accept changes 
And they could chose which changes they would like to keep and destroy
There’s a very complex system behind this idea. But they could do it I guess, Epic’s staff are too smart.
What you describe has already been in development for many months by the user YannickLange as an UE4 plugin.
The plugin in question is called MultiEdit - Collaborative Level Editing Plugin and YannickLange could really use your help by voting on his Multi-Edit Trello Board so that he can prioritise features based on demand.
NOTE: This plugin is still in its very early stages of development and as of typing this there is currently no means to purchase and download the plugin but fingers crossed that will change sometime this year.