What Is a Prototype: A Guide to Functional UX

Yasin Shaikh
7 min readFeb 27, 2023

Prototyping is one of the most critical steps in the design process, yet prototypes still confuse some designers and project teams.

A common misconception is that some designers refer to mockups as prototypes — which can confuse those who know otherwise! Prototypes are also not a series of sketches or a pixel-perfect prelaunch interface.

In this post, we’re going to define what prototyping is and explain the different variations. We’ll also show you how to make clickable user interfaces, and most importantly, how prototypes can optimize the user experience.

What Is a Prototype?

A prototype is “A simulation or sample version of a final product, which UX teams use for testing before launch.”

The goal of a prototype is to test and validate ideas before sharing them with stakeholders and eventually passing the final designs to engineering teams for the development process.

Prototypes are essential for identifying and solving user pain points with participants during usability testing. Testing prototypes with end-users enables UX teams to visualize and optimize the user experience during the design process.

Engineering is expensive, and making changes to a final product is often not as straightforward as teams anticipate. So, finding and fixing errors during the design process is critical!

Prototypes have four main qualities:

  • Representation — The prototype itself, i.e., paper and mobile, or HTML and desktop.
  • Precision — The fidelity of the prototype, meaning its level of detail — low-fidelity or high-fidelity.
  • Interactivity — The functionality open to the user, e.g., fully functional, partially functional, or view-only.
  • Evolution — The lifecycle of the prototype. Some are built quickly, tested, thrown away, and then replaced with an improved version (known as “rapid prototyping”). Others may be created and improved upon, ultimately evolving into the final product.

Another common misconception about prototyping is that it only needs to be done once or twice at the end of the design process — not true.

One of our mottos at UXPin is “test early and test often.”

According to Elementor’s Director of UX, the website building platform’s designers — average four to five prototyping sessions, depending on the complexity of a given design.

You should prototype every possible iteration of your design — even your early basic ideas for solving a user need. Prototyping shouldn’t be reserved only for beta tests of the final version; you should test any and every version of your product!

If testing a prototype produces new insights about how end-users will interact with your product, then it’s worth taking the time to gather user feedback and iterate — whether that’s paper, low-fidelity, high-fidelity, or HTML.

We’re going to explore prototypes in three types of prototypes: paper, digital, and HTML.

Paper Prototyping

Paper prototyping works best during the early design stages where UX teams collaborate to explore many concepts fast. Team members sketch ideas by hand using simple lines, shapes, and text. The emphasis is on lots of ideas and speed, not aesthetics.

UX Teams lay paper screens on the floor, table, or pinned to a board to simulate user flows. A common practice for testing these prototypes is to have one person play “the product,” switching the sketches according to how the real user behaves.

Advantages of Paper Prototypes

  • Fast — You can sketch a prototype in minutes, which is why paper works so well for testing lots of ideas. You can draw a prototype quickly (even during a brainstorming meeting), so you haven’t wasted more than a few minutes if an idea falls flat.
  • Inexpensive — You only need a maker pen and paper to create prototypes, making the process cheap and accessible.
  • Team-building — Paper prototyping is a collaborative effort, and often teams have fun coming up with fresh ideas. It’s a fantastic team-building exercise, and these free-thinking sessions often inspire creativity.
  • Documentation — Team members can keep physical copies of paper prototypes, notes, and todos for quick reference during future iterations.


  • Unrealistic — No matter how skilled the art or craftsmanship, paper prototypes will never be more than hand-drawn representations of a digital product. So, while they’re quick to draw, paper prototypes produce little or no results when doing user testing.
  • False positives — Sometimes, paper prototypes don’t validate ideas properly. What seems like a good idea on paper might not work effectively in a digital wireframe.
  • No gut reactions — Paper prototypes rely on the user’s imagination, adding a break between seeing the stimulus and responding to it. That “gut” reaction is crucial for a successful UX.

Considering these advantages and disadvantages, we recommend paper prototyping only during early-stage design. Once you move from paper to digital, there shouldn’t be any reason to revisit hand-sketched prototypes for the same designs or user flows.

For more information on paper prototyping, check out these helpful resources:

Digital Prototyping

Digital prototyping is an exciting part of the design process. Prototypes start to resemble the final product allowing teams to test and validate ideas.

There are two types of digital prototypes:

  • Low-fidelity prototypes: a user flow using wireframes
  • High-fidelity prototypes: a user flow using mockups

Low-fidelity prototypes allow research teams to outline basic user flows and information architecture. High-fidelity prototypes go into more detail, testing user interfaces, interactions, and how usability participants interact with a product.

Designers build prototypes using design tools like Figma, Adobe XD, and others. Sometimes non-designers, from product teams use Powerpoint or Google Slides to simulate user flows.

Advantages of Digital Prototyping

  • Realistic interactions — Testing with high-fidelity digital prototypes lets UX teams see how users interact with the final product, thus effectively iron out any usability issues.
  • Flexibility — Test early and test often! You can start with lo-fi prototypes that become progressively more advanced as the product design process moves forward.
  • Speed — While paper prototypes might be the fastest way to test ideas, digital prototypes are the quickest way to test usability issues. Once a product gets to the engineering stage, changes cost significantly more time and money.


  • Learning curve — Before you can build a prototype, you’ll need to learn and understand the software — which is why product teams often use Powerpoint instead of a specialized design tool. The good news is that most design software incorporates the same tools, so it’s relatively easy to switch between them.
  • Cost — As you move from low-fidelity to high-fidelity prototyping, time and labor costs increase.

A prototype’s success depends on teams outlining clear objectives and KPIs for each usability study. Without a proper plan, designers can get side-tracked, adding unnecessary features and interactions!

Here are some helpful resources for creating digital prototypes:

HTML & JavaScript Prototyping

On rare occasions, teams might build HTML & JavaScript prototypes to get more accurate results. The downside to this approach is that coding comes with considerable time and technical costs.

Product designers (and non-designers) can create code-based high-fidelity prototypes that look and function like the final product.


  • Final product functionality — HTML prototypes provide participants with an accurate model of the final product.
  • The technical foundation for the final product — Building an HTML prototype provides researchers with a valuable research tool and provides developers with the foundations for building the final product.
  • Platform agnostic — You can test your prototype on virtually any operating system or device, and the user won’t need to run outside software.


  • Dependent on designer skill level — Your HTML prototype is only as good as your ability to code. Poorly coded prototypes could introduce usability issues that don’t have anything to do with UX design!
  • Inhibits creativity — Coding takes time and focus to build a usable prototype. Designers might not achieve the same level of innovation or creativity as using a familiar design tool.

Here are some helpful resources on HTML prototyping:

The Prototyping Process

There’s no single best process for prototyping; it all depends on the product and application. Below are the three most effective prototyping processes, each intended for different scenarios.

Paper => Lo-fi Digital => Hi-fi Digital => Code

Most designers follow the paper => lo-fi digital => hi-fi digital => code process for prototyping.

Teams collaborate to develop lots of ideas, sketching wireframes on paper and creating user flows before committing to digital. Here, UX teams will use common brainstorming methods like crazy eights or asking “how might we” questions to get into an end-user mindset.

A lo-fi digital prototype (wireframe) tests crucial elements like navigation and information architecture early in the design process. Teams can use feedback to make quick adjustments to wireframes before committing to mockups.

Once teams complete navigation and information architecture, designers build mockups resembling the final product — adding color, content, interactions, and animations.

When researchers have exhausted testing, UX teams hand over designs to engineers to develop the final product.

Paper => Lo-fi Digital => Code

Going from Lo-fi prototyping to code is an old approach that few teams ever use these days. While lo-fi prototyping is cheap, it doesn’t catch many of the usability issues high-fidelity prototypes expose.

Product developers without design skills might use the paper => lo-fi digital => code method because it’s quicker for them to code than learn how to use a design tool.

HTML Prototyping => Code

Solo developers might skip any early prototyping methods and go straight to code. With no one to bounce ideas with, it can make sense for a developer to jump straight in.

Essentially, the prototype creates a foundation and evolves into the final product. This prototyping method is only effective for skilled product developers with efficient workflows.

Even designers with excellent design skills might want to avoid this method of prototyping. Low-fidelity and high-fidelity prototyping are significantly faster than building and editing code.

Paper =>— Hi-fi Prototyping => Code

You can accelerate the UX process through rapid prototyping. Create fully-functioning high-fidelity prototypes using UI code components to provide participants with a life-like model of the final product.