Often confused with a wireframe, a prototype is a medium or a highly detailed representation of the final product. It simulates user interaction with the interface and allows the user to rate the content and interface and test the primary options for communication with the app. Though, prototype may not look exactly like the final product, but it definitely should not be sketched in shades of gray. In addition, interactions must be modeled in a way that closely mimic the final product.

A prototype is a preliminary model of our product used for testing. You’ll often build different fidelity prototypes during the product development process.

During early stages, you can build paper prototypes (low-fidelity) with pencil and paper to validate concepts or flows. Later on, with flows and concepts validated, you can jump on design software, like Sketch, to build a high-fidelity prototype. Instead of looking like a doodle, prototypes will look like apps on your mobile device do and can be used to fine tune details on your UI.