Zyng is a tool that converts a running software application into a narrated product demo. It allows an AI coding agent to interact with the application via the Model Context Protocol (MCP), driving the app through its features while Zyng records the screen and generates a voiceover. The output is a finished MP4 video that requires no camera, manual screen recording, or post-production editing. Users can also create demos directly through a web studio interface without an agent. The platform operates on a credit system, where one credit equals one second of rendered video. New users receive approximately eight minutes of free video output without requiring a credit card. Videos produced with the free tier include a "Made with Zyng" watermark, which can be removed by purchasing credits in amounts such as $10, $20, or $50. There is no subscription model; users pay only for the video length they need. Typical use cases include investor updates, sales follow-ups, product launches, and onboarding explainers. The workflow begins by providing the agent with the application's URL. The agent reads the source code to obtain real selectors, then clicks through each flow over MCP while Zyng records the screen. Zyng writes the voiceover, stitches clips and scenes, and returns a finished MP4. Passwords are resolved on the user's machine and never reach the agent. Users can also drop in a spreadsheet, and Zyng will narrate it with charts using the actual numbers, down to the currency. Technically, Zyng is deterministic: the same input produces the same video every time, and when the underlying data or application changes, the demo can be re-rendered to stay in sync. The agent authors Playwright steps from the user's own code, ensuring selectors are accurate rather than pixel-based guesses. Zyng records the real product with real data, not synthetic avatars or stock footage. Every clip on the website is a genuine Zyng output with no post-production editing.