A prototype is an interactive simulation of a product or feature used to test ideas, validate flows, and gather user feedback before full development. It can range from simple clickable wireframes to high-fidelity mockups that mimic final visuals and behavior.
Prototypes allow designers and stakeholders to explore how a user will navigate an interface, catch usability issues early, and iterate quickly. They’re essential for aligning teams, reducing development risk, and ensuring that the product works as expected—long before any code is written.