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Why do we prototype the user interface design?

Everyone wants to see if their project is going to be a success. How do you do that? By creating a model of it as close to the final version as possible and running a simulation with it.

16 August, 2022
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Everyone wants to see if their project is going to be a success. How do you do that? By creating a model of it as close to the final version as possible and running a simulation with it. That’s why digital products get rigorously tested before deployment to fix any issues and ensure favorable feedback from the audience. What about design? Why do we prototype the user interface design?

Fixing potential issues is just one side of the coin. There’s so much more to prototyping than that. Today, we’ll look into what is called a user interface prototype, what are its types, the role it plays in the UX/UI design and development process, and how we, as a UX and UI design and consulting specialists, go about prototyping your product’s UI, and why it’s so important in ensuring the project’s final quality.

What is user interface design prototyping?

When designing user interfaces for sites, web or mobile applications, or any other digital products, UI designers like to create a close replica of the design to see how it would look like as a finished product. This replica, which is precisely what the UI prototype is, does not contain any code. It does, however, set to include almost every element of the final user interface design, as well as most of the interactions.

Before we finish building a custom user interface, the only way of checking out where the design is going is by looking at static screens. Yet when UI designers complete the prototyping process, its final level of interactivity allows them, their users, and clients to click the elements the way they’re meant to be eventually interacted with.

An advanced prototype contains the product’s backbone - its structure, primary click-through navigation, and then layers of more complex interactions such as scrolling, dropdowns, menus, various effects, carousels, etc. They can also be either single-page or multiple pages with clickable elements and transitions between screens that users need to finish a task.

So, what does a UI/UX designer do before creating user interface prototypes for them to be as helpful and accurate as possible? The following four tasks are a must:

  • Requirements gathering
  • User research
  • Information architecture
  • A wireframe and a mockup (optional but helps with prior visualization)

The difference between a wireframe, a mockup, and a prototype

These three types of design visualizations can sometimes get confused by non-designers. They all represent different stages of design. A wireframe is an overly simplistic representation of the product’s design, containing only structure, while a mockup is a more detailed yet still static depiction of how the product and its features will look like.

A prototype, on the other hand, is a mockup that is furnished with interactive elements and can have any level of fidelity. Out of all three, prototypes are the only ones also focused on your product’s functionality.

Wireframe vs mockup vs prototype
Wireframe vs mockup vs prototype

The role of prototyping in UX/UI design

The UI prototype itself plays many roles - usually, it’s either a communication tool, a working demo model, a testing ground, a feedback collector, or a design template, and so on. On its own, it’s not a deliverable. A prototype can only be used to test the product’s user interface design, not the product in question.

The role of the prototyping process in UX/UI design is much more complex. It’s a powerful tool that helps us, designers, carry out various handy experiments and check our interface assumptions beforehand. If we were to test them after we’ve already finalized the design, it would’ve been completely impractical, not to mention costly.

Another role that prototyping plays is stakeholder validation. As much as we would like to proceed with all our fancy ideas, it’s our clients and users who have the final say on what we get to keep and what we should change. Prototyping the design helps communicate the design thinking, visuals, and functionality and validate our ideas before we hand off the project to developers.

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The importance of prototyping in user interface design for systems and software

It’s hard to overstate the importance and benefits of prototyping in UI design. It helps us avoid expensive fix-ups, gives us the needed speed to test out ideas, and thus accelerates time-to-market, which the stakeholders especially like. Overall, prototyping in user interface design and its subsequent usability testing for any type of system or software helps design teams to:

  • Save time and resources. When we create and then test the prototypes, we’re able to find potential problems before they seep into the development process. It’s much more cost-effective and practical to make changes before the design is finalized and especially before the developers come in to do their magic.
  • Boost creativity. Testing the prototypes beforehand and the freedom to make any change we want gives us a nice creativity boost and lets us play with the interface and try different ideas.
  • Improve product adoption. Prototype testing helps see the mistakes in the graphical user interface accessibility and user experience, fixing which helps improve the user engagement and adoption rates.
  • Receive feedback from the client. The prototype itself is an excellent communication tool with the stakeholders and even the potential audience - we can use it to demonstrate what we’ve done so far and collect feedback and ideas.
  • Communicate. We also use it to communicate and collaborate with each other within the design team, as well as with our folks from marketing and development. It’s easier to display ideas on a prototype than to explain them any other way.
  • Identify unnecessary elements. Without a prototype, there’s no way of seeing if the UI component or feature is necessary for the final version of the project, leading to developers wasting their time working on them.
  • Prepare for the future. You can use your prototype to provide maintenance or make some changes to the product’s design way after it’s deployed if the need ever comes.

Ways of prototyping user interface designs for designers

There are two ways a website and app development company would go about prototyping user interfaces. A bare minimum would be creating paper prototypes. A bit higher fidelity requires the use of special tools. Let’s break down each of these methods.

Creating paper prototypes

Best during the initial stages of the design process, paper prototyping is precisely what it sounds like - a prototype scribbled down on a piece of paper. It’s super low-maintenance and only requires a pen and paper, and a sprinkle of creativity, of course.

Paper prototyping hardly costs any money, besides going to the store if you’ve run out of pens, and allows you to swiftly sketch some ideas and concepts without going into too much detail. Speed and quantity of different ideas are key, only emphasizing the simple shapes, lines, and user flows.

While the inexpensiveness and fast results are usually what drive designers to sketch ideas on paper, they definitely shouldn’t be the only prototype drafts simply because they are obviously unrealistic and can’t be used to properly validate any ideas or insights on the potential audience.

Using design tools

You can find many helpful tools for prototyping currently on the market. All of them have pros and cons, so combining a few is sometimes best to achieve the desired results. Here are some of the most functionality-rich ones you can find today.

Figma. This versatile tool can handle all things design - from wireframing and prototyping the user interface and user experience to managing the design system and handoff. This cloud-based platform for both Mac and Windows can handle the entire workflow with no code.

Adobe XD. This next vector-based tool is also used for various prototyping and collaboration needs. It has two modes - for prototyping and overall design. The latter allows the creation of static designs, which you can then turn into prototypes by adding interactive elements.

InVision Studio. With this also vector-based prototyping and animation tool, designers can work on their whole design from start to finish. InVision Studio features an easy-to-understand drag-and-drop interface, multiple vector drawing tools, and numerous layers and canvas.

Axure RP. One of the most famous design tools, Axure lets you create mockups and highly interactive HTML prototypes for both website and mobile app development primarily through drag-and-drop features, resizing, and multiple widgets.

Sketch. Also an all-in-one design platform, Sketch is considered a rival to Figma, offering a similar set of functionality and editing tools when it comes to static and interactive prototyping. It’s excellent for beginner UX and UI designers; however, it’s only available on macOS. This last tool on our list is only available when working from a browser. A handy prototyping solution for the entire team working on the project, from designers to marketers, it offers an intuitive interface and quite a few ready-made design elements.

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High-fidelity vs. low-fidelity prototyping

Apart from paper prototypes, UI designers also create digital prototypes that consist of two types - low-fidelity (lo-fi) and high-fidelity (hi-fi). Low-fidelity prototypes contain only the basics - simple outlines, screen layouts, and element positioning, sometimes including sizing, spacing, and element prioritization. The screens display only the core of the future navigation.

Regarding the visual hierarchy, low-fidelity design depiction includes some if any of the visual attributes of the final user interface and only an overview of the future content. The reason for such a simplistic visualization is to keep the designers’ attention on the UI fundamentals - information architecture, navigation, and basic layout.

High-fidelity prototypes are exactly what we meant at the beginning of the article by describing the prototypes as the design model or a simulation being as close to the final product as possible. Being one step removed from the finished project, hi-fi prototyping involves adding the entire layout with the navigation, spacing, and positioning much more detailed than before.

High-fidelity also includes all the final UI furnishings like fonts, styles, color palettes, the rest of the design system, animations, and interactive elements where even the links are clickable, just like in the finished product. This type of prototype must also contain all the final content, such as product descriptions, articles, and images.

The standard UI design process in our and many other teams usually goes like this: a few paper prototypes during the brainstorming session and initial collaboration process where we come up with ideas, followed by a low-fidelity prototype, which then gets tested before evolving into a high-fidelity one. Next comes developer handoff, and coding ensues.



Prototyping is one of the most crucial stages of the design process. They are relatively easy to create - much more manageable than remedying mistakes at a considerably later stage, especially when it all gets put into code.

The essential user interface design consists of numerous different elements and interactive layers, each of which gets progressively more complex and, therefore, harder to add without a working prototype you can quickly test and modify.

In the long run, our team believes creating a prototype proves a worthwhile endeavor, saving our designers both time and headache on future alterations.

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CEO and Founder of Merge

My mission is to help startups build software, experiment with new features, and bring their product vision to life.

My mission is to help startups build software, experiment with new features, and bring their product vision to life.

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