Understanding prototype fidelity levels

Deciding when to test your prototype depends on several factors, like time, budget, resources, and the product or feature you’re designing.

The word prototype might suggest a model of the finished product, but in reality, they don’t need to be perfect. In fact, there are different levels of fidelity.

If you’re in the early stages of the design process, you might create a low- or medium-fidelity prototype. If you’re nearer to the end of this process, you might opt for something with higher fidelity. Fidelity is the level of reality that your prototype has.

Let’s explore these different levels of fidelity in more detail.

Low- and medium-fidelity prototypes

The earlier you can test your prototypes, the better. Low-fidelity prototype testing happens in the earlier stages of the design process with a paper or digital prototype. Use them to generate and share feedback and ideas with stakeholders so you can quickly iterate your designs.

What are you testing at this stage?

• Whether the layout makes sense to your users.

• Experiments in your initial designs.

• The information architecture.

• Basic interactions with the design.

As you take user feedback onboard and improve your design, retest new prototypes using a medium-fidelity prototype. At this stage, you can also add copy.

High-fidelity prototypes

Once you’ve tested and taken in user feedback on your low- and medium-fidelity prototypes, you can move onto creating a high-fidelity prototype. 

This is interactive and closely resembles the final product.

At this stage, you shouldn’t expect huge problems to emerge. Use a high-fidelity prototype as a last step in your design testing process to validate your final design and uncover any hidden usability issues before handing over to the development team.

What are you testing at this stage?

• The overall design direction.

• The copy, menu links, and information architecture.

• User flows: Can users find their way when completing a task?

• UI components, e.g. drop-down menus, pop-ups.

• Graphic and visual elements, e.g. image quality, text readability.

Live data prototypes

A live data prototype uses data or APIs to create dynamic experiences. It’s much like the final product, so you might use it if you wanted to test software solutions in real-life environments and conditions.

Building a live data prototype is more involved than a low- or high-fidelity prototype, as you’ll need a developer. But it can be a useful way to learn how your product performs with users in the wild and generate data about how the final product will work. And if the test goes well, you’re already on your way to production-quality software.

Feasibility prototypes

A feasibility prototype focuses on a key feature, technology, or component of the product. You might opt for this type of prototype if you wanted to test something considered high-risk, like a specific feature innovation.

The aim with a feasibility prototype is to establish evidence that the feature, technology, or component will work. You might use it in the early stages of the development process in order to assess and reduce future risks.