A prototype is an early model of a design used for testing and refinement. It can be as rough as a paper sketch taped to a wall or as polished as a clickable digital app. The point is to learn something before committing to full production. Prototypes invite feedback. They make abstract ideas tangible enough to critique.

Designers use different levels of fidelity depending on the question. Low-fidelity prototypes, often paper or simple wireframes, test structure and flow. High-fidelity prototypes, built in Figma or code, test visual design and interaction. A paper prototype of a mobile app can be tested in an afternoon. A coded prototype of a physical product might take weeks. The trade-off is speed versus realism.

Types of prototypes

• Paper prototypes for quick flow testing.
• Clickable digital prototypes for interaction testing.
• Wizard-of-Oz prototypes with a human behind the scenes.
• Functional code prototypes for technical feasibility.

Prototypes are meant to be thrown away. If a prototype survives unchanged into the final product, the team probably did not learn enough from testing it.