How We Built a Free Browser-Based Screen Recorder

At Flat.social, we build tools for remote teams to connect, collaborate, and have fun together. Our platform already handles real-time video, spatial audio, and interactive games for virtual offices and events. So when we decided to add a free screen recorder to our toolkit, we had a head start on working with browser media APIs. But building a screen recorder that feels polished, works reliably across browsers, and never touches a server turned out to be a deeper engineering challenge than we expected. This article walks through the technical decisions we made, the browser APIs we used, and the problems we solved along the way. Why Build a Screen Recorder? Our users already use Flat.social for remote team collaboration, online brainstorming, and running virtual workplaces. A common request we kept hearing was: "Can I record what's happening on my screen to share with teammates who couldn't make it?" People wanted to capture product demos, walkthroughs, and async updates without instal