A simulation of a product or feature used to test and validate design decisions before full development. Prototypes range from low-fidelity paper sketches to high-fidelity interactive mockups, and are most valuable when tested with representative users.
Common contexts
- Building a clickable Figma prototype to test whether users can complete a multi-step checkout before a single line of code is written
- Creating a paper prototype of a mobile navigation structure to run five guerrilla tests in an afternoon
- Producing a high-fidelity interactive prototype for a stakeholder demo to secure executive sign-off on a redesigned onboarding flow
Use when
Build a prototype whenever you need to test a hypothesis about user behaviour, validate a new interaction pattern, or secure stakeholder alignment on a complex flow — and when the cost of building it is lower than the cost of discovering the problem in development.
Avoid when
Don't build a prototype to avoid making a decision — if the team hasn't aligned on the problem to solve, a prototype will generate feedback that looks like learning but is actually just opinion collection dressed up as research.
The fidelity of a prototype should match the fidelity of the question — testing information architecture requires nothing more than boxes and arrows, and polishing visual design before structure is validated is a common, expensive mistake.
Real-world examples
- IDEO built cardboard and foam mockups of the first Apple mouse to test hand grip before writing a single line of code — a physical prototype that shaped the hardware form factor of every mouse since.
- Figma's live-share prototype feature allowed the Airbnb design team to test their 2020 category redesign with users in 12 countries simultaneously, compressing a 6-week international research trip into 2 weeks of remote sessions.
- Amazon's 'working backwards' process mandates that every new service begins with a press release and FAQ prototype — a document-level artefact that functions as a prototype of the customer experience before engineering begins.