This is a really cool and ambitious project. Although some mention ShareJS, I would say that the OT portion more closely resembles that employed by Firebase in their Firepad project  (in that no centralized server manages ordering and history). Actually, this system has many of the features of Firebase in a self-hosted package.
As a user of ShareJS (for the real-time collaboration on Plunker ), I can see some interesting benefits offered by TogetherJS; the system has cursor and presence features out of the box.
That being said, the main drawback that I see in TogetherJS is that it seems to be tightly coupled in a way that it is hard to take smaller parts of the overall system. It would be great if the P2P network system could be extracted and plugged into a node.js Stream interface. That would allow the code to plug into a whole ecosystem of interesting libraries .
I'm really excited by all the powerful libraries that Mozilla has been pumping out these days. The web is a great place to be.
[Author here] The big way TogetherJS differs from many of the other realtime products out there, like Firebase or (to a lesser degree) ShareJS, is that it doesn't do any storage. It coordinates real-time sessions, but it's not there to take the place of the application, instead it augments the application. If your application has persistence, it has traditional persistence. Whatever auth system you have is your own. At the same time while it dodges any persistence, it extends the scope beyond what those other tools typically do to include more with session management and the standard tools that I think are needed for collaboration. There's nothing exciting about text chat, but you need it anyway.
Still, ignoring persistence I think will help keep the surface area of the TogetherJS smaller compared to some other tools. Or at least focused on other things.
People have mentioned the idea of being able to chop TogetherJS up before, but I have a hard time seeing how that would actually work. For instance, the architecture is built around a pretty dumb server, so hooking into Streams would seem counter to that principle. And just allowing for the possibility would add a lot of complexity. Ultimately the UI is actually the bulk of what makes up the TogetherJS code (or maybe it's the part I find hard and so I feel like I spend a lot of time with it), and I don't know how to make this kind of UI while being modular. Without the UI I don't think it's nearly as compelling a project (becomes more like ShareJS, or Firebase, or Google Drive Realtime API – neat but a big investment, and sometimes only appropriate for greenfield projects.
Anyway, I'm certainly interested in how people want to extend or integrate with TogetherJS. I'm skeptical of splitting it up into pieces, as it is theoretically easier to do things that way, but I expect in practice it will just leave a confusing pile of pieces that aren't fun to put back together. But that doesn't mean that there aren't use cases worth exploring... and with some creativity there might be other approaches to handling those cases.
[mozilla employee here] There's no catch except an absence of a commitment to keep running it. Mozilla Labs is charged with figuring out how to make the web better. We think this could help make more apps collaborative. You tell us if we're right.
It doesn't seem to be a P2P system, since it requires a server. According to the docs, "This server does not rewrite the messages or do much of anything besides pass the messages between the participants"  , so it's not really P2P.
I'm fairly sure the Firebase requires a server too... (their server, or else they couldn't charge for it).
On principle we keep the server simple, echoing messages back and forth between clients. In practice it's quite hard for two browsers to connect directly to each other, and while we want to support that kind of architecture in order to get it working we still need to simulate P2P using a server.
WebRTC makes it possible, but not easy, nor abstracted. You still have very long connection strings to establish the connection, and those strings change as you move around, so it's not something we'd want to ask users to send to each other in order to establish a connection. The approach usually used is a server where the two people rendezvous to exchange the connection strings. That server is kind of like what we have – but then once it's in place, changing over to WebRTC just doesn't seem as exciting. (And even then the connections are slower to establish and less reliable than WebSockets.)
We provide wysiwyg editor integration (Aloha-Editor) with presence and remote cursor. We are working on a hosted/downloadable service with low-level data-sync api and high level wiki features: https://wikidocs.com
You can actually do that in Plunker right now by having an `index.md` file instead of `index.html` .
In the absence of an html index, the plunker preview server will try transpiling to html from different languages. Markdown is currently supported.
Also transpiled are things like less, scss, coffee-script and more. Essentially, your html requests a file with the target suffix (e.g.: .css) and the preview server will search for compatible source files to transpile to that target.
Actually, after testing some more, it does not work. jqueryUI dialogs are prevented to open (for one thing). And, since I change the url hash, it likely messes with the changes introduced by togetherJS ... which, currently, prevents it from working collaboratively. Still, neat idea - especially if I can get it to work.
I'm getting pretty tired of people releasing js libraries and not telling you that they depend on jQuery. You don't just add that script to your page, you add that script and jQuery to your page. Stop assuming everyone already has jQuery, guys.
This looks fantastic. I just have a question for the author (+ Mozilla). Since this is a hosted service, I'm a bit reluctant to integrate it, because I'm not sure what we should expect from Mozilla on this project. Is this a cool open source project that will get support for a little and then fade away? Is this something that a team is really behind and is going to continue to support and extend? Is it expected that most people will just host their own version? (doesnt seem that hard to do, but there is a lot of appeal in not managing the server for this at all)
If this was from a startup I would expect a free trial and then a pricing page that told me what happened if I had X # of users or Y # of requests, but without that info, it seems there is a lot of missing information. Does Mozilla just plan to keep it hosted indefinitely? Or how do you plan to handle users of different sizes? Our use case now is small, but in choosing to go with this tool (vs. Firebase or something else), the switching costs down the road are relevant.
I'm planning to try it out in a small test either way, I'm just curious about more details on the mozilla-hosted version.
I gave this a go with a "thick-client-in-browser" app that we are writing here . I had to hack the code a bit (e.g. remove the clickable class check in the event simulator) but I was shocked how well it dealt with this scenario and how little effort I had to put in.
It's still a long way off from supporting this type of web page (e.g. dragging does not work, and would love to submit a PR if I only had the time to dig in more); but the almost-instant success with it was impressive. Good work Mozilla.
[Team member here] We haven't been very focused on the hosting story, in part because lots of people have their own requirements, and we can't predict what they are. And maybe because predicting what they are is boring. I know some hooks for New Relic have been added to the server. It's also a super-simple server that only keeps things in memory, so it's pretty darn easy to handle. Just one file: https://github.com/mozilla/togetherjs/blob/develop/hub/serve... (and only one dependency, for WebSockets).
Looks cool! I wonder how you'd negotiate authentication with this... both users logged in presumably, you could record edit author as whoever clicked the save button (or upon each action in a "real time" saving application).
Both people are accessing the website as themselves. If one person doesn't have permission to see a page, for instance, then they won't see it. And yeah, whoever hits save is the saver ;) Doing something richer than that requires application-specific integration, which we want to support, but we also want to take cues from developers about what that should actually look like. This is one idea we have along these lines: https://github.com/mozilla/togetherjs/issues/372
Another great project from Mozilla, congratulations. I'll definitely give it a try.
Sorry to blow my own horn, but a few months ago we launched a similar project called Quolony https://quolony.com (we are a small startup from Salamanca, Spain).
Right now we are working as a free service and we plan to publish it as open-source in the next few months.
People can use it individually using a browser extension or in whole sites including our library.
We have avatars, synchronized text selection, private and public chats, persistence, cobrowsing, file transfers and a lot more.
I've been helping test Quolony for a while and the potential for this technology is great. In particular using it as a browser extension with the instant link sharing and cobrowsing gives those otherwise solitary web browsing sessions a certain feel of the metaverse that could be.
As the meme goes, this puts Internet on your Internet.
Here's a bookmarklet I threw together. You can go to the link given by someone else and then click the bookmarklet to join their session. It messes up if you change pages, though. Maybe there's a way to fix that.
Pretty interesting that it maps reactive UI elements like bootstrap divs which resize properly!
I want to implement a real time Collaboration editor like google docs because I want to keep data on my own servers.. Can anyone suggest me architectural points to build that...what should be stack on server side, how to send edit diffs etc..
I'm working on something similar: https://wikidocs.com. Although our's closed source at the moment (can't say whether or not it will remain closed), we will provide a downloadable package you can run yourself.
Looks like this would be great for customer support, and could be a nice alternative to olark. It can be configured to automatically post the invite url to another dashboard, where one of the CS execs can pick up and walk the user through.
This is very similar to what we do at Firefly (http://usefirefly.com), except we support all the way back to IE 8. Kudos to these guys for putting this together - especially if it works well. It's a lot harder than it looks.
We recently built openmic.io to add sound annotation to pictures & websites. This pops up just as we started looking into real-time collaboration. I guess it validates the need for better in-context collaboration tools.