Sketch is a prototyping and design tool for macOS, available from since 2010, with quite the reputation. For many UI and UX designers using Apple hardware, Sketch is THE software to use, covering every stage from wireframes through to final handoff. It offers advanced collaboration, feedback, and permission settings, and there is even the option to use the browser version.
Dutch developer Sketch B.V. has overseen this tool since the beginning, with its primary macOS version complemented with prototype preview apps on iPad and iPhone. There is no Windows version, and no Android app.
