Screenflow is a single flowchart document tool that helps visualize mobile and web app ideas. It aims to reduce complexity and improve communication between stakeholders, designers, and developers. The tool allows users to draw flowcharts with screen specifications, write details for each screen, and share the documentation via a URL. This helps address problems with designing apps without experience, misunderstandings during development, and a lack of reference architectures. While there are drawing, UX, and project management tools, Screenflow is designed to focus specifically on visualizing app ideas and specifications in a single shareable flowchart document.