togetherjs

TogetherJS is a piece of code that website owners can add to their site to let visitors collaborate with each other in real-time. Imagine you're browsing a website and get stuck — you could invite a friend to look at the same page with you, and you'd both see each other's mouse cursors moving around, watch each other typing edits, and navigate together. It's like screen-sharing, but built right into the webpage itself.

The system has two simple parts. There's a lightweight server that acts as a messenger, passing information back and forth between people using the site — it doesn't store anything or do much work. The real intelligence lives in the client-side code, which runs in each person's browser and handles all the collaboration features like tracking cursors, syncing edits, and keeping everyone's view of the page in sync. If you want to use this service, there's already a public hub server running at togetherjs.com that you can point your website to, so most people don't need to run their own.

Website owners would use this if they want to offer real-time support or group browsing features to their visitors. For example, a tutorial site might let instructors and students view the same content together, or a customer support team could invite a struggling customer to collaborate on finding a solution. The website owner includes a small piece of code that downloads the TogetherJS library, and suddenly users have the ability to invite others and see each other working.

Building and deploying TogetherJS requires some standard web development tools — specifically Node.js and Grunt for building the code — but nothing exotic. The codebase uses a build system to compile styles and generate some files before deployment, and there are tests you can run manually in a browser. The README doesn't go into detail about performance or scalability tradeoffs, but the architecture is straightforward enough that most developers should be able to understand how it works by reading the code.