There comes a time in every project when an idea transitions from conceptual to actual. In website and app design that time generally comes during the prototyping process. Prototyping can be done in a range of fidelities, or levels of detail, from low to high. Low-fidelity prototypes can be a great tool for quickly iterating design ideas and starting usability testing early in your design process, but the type of experience they offer is quite removed from a product’s endgame. High-fidelity prototyping is when things start to feel and look real.