To test our solution with real users, we need a prototype that looks and feels real. We spend all of day 4 on building a high fidelity interactive prototype in which information flows seamlessly from one screen to another, just like it would in real software.

Tools
To build a high fidelity prototype that functions like real software, no single tool is perfect. It’s good practice to use a combination of different tools instead. As of this writing, we recommend:
- Sketch: For making static screens
- Invision/Marvel: For quickly connecting a large number of static screens into a click through prototype
- Framer: For building prototypes with animations and live data
Roles
Building a prototype isn’t a one-man job. To make it as real as possible in just a day, you will have to work together as a team with clear roles and responsibilities. You will need:
- A writer: Responsible for all the copy for the prototype
- An asset collector: Responsible for collecting all the assets that go into the prototype
- A designer: Responsible for taking the content, designing screens and stitching them together
- An interviewer: Responsible for writing a script for the user study and conducting it.
Dry run
After you’ve built the prototype, leave room for a dry run before the actual user test. The interviewer uses the prototype to conduct a mock user test with a team member. The mock test is likely to surface some issues with the prototype or the script. Fix those issues and get ready for judgement day!