TogetherJS

Overview TogetherJS is a free, open source JavaScript library by Mozilla that adds real-time collaboration features to websites. Developers copy and paste its JS library and HTML snippet into their site or app to enable joint browsing, shared mouse cursors, and text chat. It solves the problem of adding multi-user interaction without installing server-side software or plugins. The library is designed for education sites, coding environments, content management systems, and any developer who wants users to work together on the same page in real time. Key Benefits Users can send a unique TogetherJS URL to a friend so both see the same page and interact together in real time. TogetherJS adds out-of-the-box collaboration tools with just a JavaScript snippet and an HTML button — no backend setup required. Built and hosted by Mozilla, making it safe to use and trusted for open source projects. Works on existing web pages without software or plugin installation for end users. Developers can customize the collaboration experience while keeping the default integration simple. How It Works A developer copies the TogetherJS JavaScript snippet and HTML button into their site. When a user clicks the TogetherJS button, the library generates a unique URL. The user sends that URL to a friend, and when the friend opens it, both see the same page and can interact with it together. Mouse cursors, clicks, page navigation, and content changes are synchronized in real time. Use Cases Education site developers — let students and teachers browse lessons together on the same page. Coding environment creators — enable pair programming by synchronizing code editors between two users. CMS plugin authors — add real-time multi-authoring so writers can edit content simultaneously. Video storytelling tool builders — let collaborators make videos together using shared editing sessions. .NET fiddle maintainers — provide real-time authoring environments for coding with friends. Why Choose This Product TogetherJS is best suited for developers who want to add real-time collaboration to their existing web application with minimal code changes. It requires end users to share a URL, which works well for pair programming, education, and co-browsing scenarios but assumes both participants are available at the same time. It is free and open source, hosted by Mozilla, and does not require any server-side setup from the developer.