Prototype

The difference comes down to how advanced the mockups are and to the aim of the test. A low-fidelity prototype relies on wireframes, those stripped-back screens with no visual styling, and serves to test the journey and the information hierarchy before moving into visual design. A high-fidelity prototype, built from the final mockups, is more about validating how the product is perceived, or presenting it internally in an immersive way before development.

They are three levels of the same piece of work. The wireframe is the skeleton, the structure of a screen without colours or styling. The mockup dresses that skeleton in the final design, but remains static. The prototype connects those screens and makes them clickable to simulate the real journey. You move from the plan to the finished screen, then to the navigable experience.

Any medium will do, as long as the idea is clear. Low fidelity can be tested perfectly well with paper sketches or sticky notes. As soon as you have wireframes or mockups, design software such as Figma lets you get to a clickable prototype quickly. For more elaborate interactions, there are tools that specialise in animation and advanced prototyping. The choice depends on the visual fidelity you are after and the type of interactions to test.

A prototype test is a user test like any other, the prototype being just one of the materials you can put into participants' hands. You give the user a task, you watch them navigate, and you spot where they hesitate or go wrong. The point of the prototype is that it makes this test possible very early, on a simulated basis, before any development.