But while prototyping sounds simple in theory, it’s easy to get tripped up in practice. Founders often move too fast (or too slow), polish when they should be learning, or test with the wrong audience. This results in wasted resources and missed opportunities.

In this guide, we’ll explore some of the most common prototyping mistakes we’ve seen startups make and share tips to help you avoid them.

Mistake 1: neglecting or skipping the discovery stage

We get it. You’ve got an awesome idea and you’re eager to get it out of your head and into the real world. There’s pressure to launch quickly, show progress to investors, and stay ahead of competitors.

In this rush, you may be tempted to spring right into action and forget about a critical step – the discovery phase.

Before you start working on a prototype, you need to have a clear idea of what you want to build and the objective of the prototype.

What questions do you need answered? Without proper discovery, you risk building a solution to the wrong problem or worse, a problem no one cares enough to use or pay for. Building without validating needs first can lead to wasted time, effort, and resources.

How to avoid

Before you design or build anything, start by identifying the assumptions your idea relies on. These might include beliefs about who your users are, what problems they’re facing, and what kind of solution they’re looking for.

Aim to talk with real users and have conversations around how they currently deal with the problem you want to solve. Ask about their workflows, frustrations, workarounds, and what they’ve tried that didn’t work.

As you gather insights, look for patterns. If you start hearing the same problems repeated by multiple users, you’re on the right track. Once you’ve validated that there’s a real problem worth solving, summarise your findings into a clear problem statement.

Your first prototype should test one specific assumption tied to your problem. It doesn’t need to be polished or complex. That’s another mistake that we’re going to talk about next.

Mistake 2: rushing to a high-fidelity prototype

Low-fidelity prototypes are simple representations of the core functionality and layout of your product that don’t include things like styling, aesthetics, and complex interactions. Think sketches and basic wireframes.

High-fidelity prototypes are detailed versions that closely resemble the final product’s look and feel. They are usually used right before development to validate design, usability, and functionality, or for fundraising.

A common pitfall we’ve seen is jumping too quickly into a high-fidelity prototype. Founders often feel the need to create something that looks polished and impressive, especially when trying to win over investors, partners, or early adopters.

The problem is that high-fidelity prototypes take more time and resources to create compared to low-fidelity prototypes.

This makes them harder and more expensive to change through iterations. They can also lock you into design decisions too early.

When you spend too much time making your prototype look like a finished product, it becomes harder to throw it away, even if user feedback shows it’s not working.

How to avoid

If you’re still exploring what problem to solve, you don’t need anything more than a sketch or a basic wireframe. Early on, keep your prototypes as low-fidelity as possible for as long as possible.

This gives you room to experiment, gather feedback quickly, and iterate without being emotionally or creatively attached to the output. A hand-drawn screen or a rough mockup might not wow anyone, but it’s good enough to help you gauge any flaws with your product, if the flow makes sense, or the solution meets user needs.

Picking the right fidelity at the right time is key. High-fidelity prototypes do have their place, especially later in the process when you're refining the user experience or preparing for a pitch. But getting to that stage too soon can create friction and slow down your learning.

Mistake 3: polishing your prototype until ‘perfection’

When it comes to high-fidelity prototypes or your final prototype version, making it “too perfect” can be a mistake.

“Too perfect” means you get bogged down on details, and while attention to detail is good, too much attention to detail is a startup killer. This is well understood by investors and VCs – we have personally seen products get turned down by US VCs because they were “too polished” or “too refined”.

It’s completely normal to want your first impression to be strong, especially if the prototype will be used for funding or user testing. Combine that pressure with a bit of perfectionism, and you can easily find yourself stuck in a never-ending cycle of iteration after iteration…

However, investors and early users don’t need to see perfection. They want to see potential and real value. A prototype that's overly refined can unintentionally send signals that your product is hard to pivot, which is precisely what investors want to avoid in early-stage startups.

Overly polished prototypes can also skew feedback from users. When something looks finished, people tend to respond to surface-level impressions. They may comment on the design details (how smooth the animation is or how visually appealing the UI looks) instead of focusing on whether the product solves their problem in a meaningful way.

How to avoid

You need to be clear about the purpose of the prototype and what questions it needs to answer. Set a learning goal, for example, whether users understand the core concept, testing a specific flow or how intuitive it is. Keep your focus on core functionality and usability.

You should also agree as a team on what “good enough” looks like. Once your prototype is good enough to answer your questions, stop there. Any additional time spent on visual details is likely unnecessary and will only delay feedback.

It’s also important to communicate clearly with all stakeholders that the prototype is a learning tool, not the finished product. This helps manage expectations and takes some pressure off your back.

Mistake 4: overcomplicating your prototype

Over polishing and overcomplicating are two very likely scenarios. While over polishing refers mostly to the design and cosmetic touches, when we say overcomplicating we mean making your prototype way too complex for its purpose.

Founders often want to show that their product can handle multiple use cases and serve a broad user base. But this can make your design bloated, packed with features. We know this comes from a good place, but over-engineering your prototype can overwhelm users and make it more difficult to build and test.

How to avoid

Try to stay laser-focused on one problem you’re going to solve really well. Ask yourself this: what’s the core problem you’re trying to solve right now? Limit your prototype strictly to the features needed to do that.

Remember that your prototype isn’t the final product or an MVP, it’s a targeted experiment. The simpler it is, the faster you can test, learn, and iterate.

If you find yourself wanting to add just one more feature to “make the experience feel complete”, pause and think: does this help us learn something new, or does it just introduce more complexity? If it’s not essential to the learning goal, leave it out.

Mistake 5: testing with a narrow scope of users

Last but not least, a common pitfall many founders fall into is testing their prototype with a narrow user group. It’s tempting and easier to seek feedback from friends, family, colleagues, and close circle, but relying solely on this data can limit your findings.

When you lack diversity in your testing group, it’s more likely to get misled by actions that might be accidental or in a spur of the moment. Also, people who know you are more likely to be polite, supportive, or overly positive.

How to avoid

The first step is to clearly define who your ideal users are, or ICP (ideal customer profile). Try to be as specific as possible by describing the role, behaviour, or context that makes someone a good fit. For example, a vague persona is “busy marketers”, a better one would be “freelance marketers who regularly juggle multiple client projects and rely on Google Docs and spreadsheets to stay organised.”

Testing with friends and family can still be useful for initial validation, but don’t limit yourself only to your immediate network. You can reach out via LinkedIn, Twitter, Reddit, and Slack communities to recruit more participants for testing. It’s important to test across different types of users (different ages, backgrounds, genders, etc) as you might find they have different motives for using your product.

When you start testing, try to look for trends and patterns instead of listening to individual opinions. If five out of seven people struggle at the same step, that’s a signal you need to address.

Building better prototypes

The most common mistakes we see all come from the same place: the desire to move quickly and impress stakeholders. The irony is that these shortcuts often make everything take longer. The good news is that every one of these mistakes is avoidable.

With the right mindset and process, prototyping is one of the most effective tools you have for moving fast, reducing risk, and building with purpose. But only when used strategically and for the purpose it is intended for – a focused experiment designed to test a specific assumption.

If you’re looking to improve your prototyping approach, answer the following questions:

• Have you validated the problem you’re solving with real users?
• Are you clear on what you’re trying to learn with this prototype?
• Do you understand your users’ needs, expectations, and pain points?
• Is your prototype focused and lean enough to test and modify quickly?
• Are you testing with diverse user groups who can give unbiased feedback?

If your answer is no to any of those, the best move is to pause, reflect, and refocus. Take the time to revisit your assumptions, clarify your learning goals, and narrow your scope. Such changes or even starting again early on can save you weeks or months of wasted effort later.

This article originally appeared in the July/August 2025 issue of Startups Magazine. Click here to subscribe