Demo Studio (demo.bnj.app) is a browser-based tool that turns a screen recording into a polished product demo video. The user either records their screen with the browser's built-in screen capture (getDisplayMedia) or opens a video file they already have (MP4/WebM/MOV). The tool analyses the clip by comparing consecutive frames at low resolution to find where on-screen activity happens, proposes zoom "moves" on a timeline, composites the clip onto a background with a window frame and shadow, and encodes an MP4 frame by frame using WebCodecs. All of this happens inside the user's browser tab. No account, no email, no password. Monetisation is a subscription (weekly/monthly/yearly, with a 24-hour free trial) unlocked by a licence code of the form BNJ-XXXXXXXX; free users get a 30-second, 1080p, 30fps export with a small corner watermark. Payment is processed by Stripe; Stripe is not connected yet at launch.