Are there any third party API's for online collaboration?

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API

Hi,

I am using a multimedia desktop application (PC and Mac) from a small developer, and am thinking of how this application could benefit from online collaboration.

What I have in mind is this: User 1 is working on a project on his/her computer. User 1 runs into a problem and invites User 2 via a menu in the software. User 2 is granted access to User 1's project and it is copied to User 2's computer. They can then share the files, probably with some kind of version control, and perhaps using an included chat room or similar.

There are two uses for this feature:
a) to help out (say, helping with filter settings that enhance an image/audio file/movie, and
b) to enable online collaboration between several users, for example students running the same software (like Google Apps, but not necessarily in real-time) or for studio musicians working on a project.

So, is there any software that would take care of this and serve other software with a suitable API? I am sure that the developer could come up with something similar, but I want to have a third party solution so that this will get quicker to implement and not take any direct effort from the main software development. (A parallel could be drawn to third party software for creating license keys: it's not hard to program, but it's more convenient to purchase an existing solution and focus on the main development.)

Thanks for any suggestions!

Petter

What I have tried:

I have tried to find these kinds of solutions online, but “online collaboration” and similar searches give the wrong kind of replies, so I don't know what to look for. I have also looked for answers on CodeProject.