Functional prototypes enable users to interact at an early stage with actual content and live functionality such as search and AI features.

The UX Design Institute summarizes the value of hi-fi prototyping as follows:

If you’re developing a prototype to show the user’s journey or start designing a specific feature, a lo-fi prototype might be enough to work through your challenges. However, if you’re creating a prototype for user testing, hi-fi prototypes will get you more accurate data.

These prototypes can be quickly created using

• front-end frameworks
• desgin systems
• APIs (Application Programming Interfaces)

Building these prototypes really does not take a lot of time, and they offer significant value compared to static mock-ups. For example, changes can be processed more quickly and consistently, and it is easier to make variations on a design. Also the step to the actual product implementation is shorter.

However, the biggest advantage is that using these prototypes in user tests generally leads to more reliable user feedback, because users will be more engaged with live content and functionality, something static mock-ups cannot achieve.