Most product teams spend days, sometimes weeks, building digital mockups that never survive first contact with real users. The screens look polished, the interactions feel smooth, and the stakeholders nod along in review meetings. Then real people try to use the thing, and the whole concept falls apart. That wasted effort triggers a painful chain reaction. Designers go back to the drawing board. Developers scrap code they already wrote. Stakeholders lose confidence, and momentum stalls at exactly the wrong time. The cost isn’t just hours; it’s alignment, trust, and speed. Paper prototyping cuts through all of that. It’s a low-fidelity design method that uses hand-drawn sketches of interfaces to test ideas with real users before any digital work begins. You need a pen, some paper, and about fifteen minutes. No software, no design skills, no wasted sprints. Here’s how paper prototyping works, when to use it, and how to run