Prototype

What is a prototype?

In product and user experience design, a prototype is a representation of a proposed product, service, or interaction used to explore or test an idea. It can be a paper sketch, a physical model, or an interactive simulation. It does not need to be fully functional.

Types of prototypes and fidelity

The GOV.UK prototyping guidance recommends selecting the form that suits the question. Sketches can support discussion of basic ideas, while an interactive prototype can support testing of more realistic task sequences.

Low-fidelity prototypes are rough representations; higher-fidelity prototypes reproduce more detail. Teams sometimes use medium-fidelity for an intermediate version. Fidelity can vary across dimensions: a prototype may look polished but use simulated data, or have working interactions with rough visuals. Greater visual detail does not automatically make it better for the current test.

Prototype example

A paper version of an appointment form can help a team examine wording and sequence. A clickable version can then let users attempt a booking and reveal interaction problems.

Benefits and limits of prototyping

Teams can use prototypes to discuss ideas with stakeholders, observe users attempting a task, and revise a design before committing to more development. The useful level of detail depends on the decision the test must inform.

Testing a prototype can inform a design decision, but it does not establish every property of the finished service. A prototype may omit unusual cases, accessibility behavior, performance limits, or operational constraints. Positive reactions to a demonstration also differ from successful use and sustained behavior change.

Prototype in psychology: a different meaning

In cognitive psychology, a prototype is a representative example of a concept or category. That mental representation differs from a design mockup. OpenStax’s discussion of concepts and prototypes explains this usage.