A prototype, a proof of concept and an MVP are three different tools, and each one answers a question the other two cannot. A prototype asks whether people understand and want this. A proof of concept asks whether the thing can be built at all. An MVP asks whether people will use and keep using the smallest real version.

They get used interchangeably, which is how founders end up building the expensive one to answer a question the cheap one would have settled in a week.

Prototype: showing the idea, not building it

A prototype is usually a non-functional representation of your product, just enough to communicate the core idea. It is not an MVP, and it is not a Lovable build or a Replit app. You are alpha testing the idea.

The goal at this stage is not to build the product. It is to have something that illustrates it, either by demonstrating it or by showing it, so you can take it around to people and get their reaction.

Two things I would tell you about prototypes:

Keep it rough on purpose. A prototype that shows potential without dictating what the product has to be is doing its job. A lot of developers build first and then show people, and what happens is that users get distracted by what is there. They stop imagining and start reacting to your pixels. It is better to validate a concept than to validate with the product.

Put things in it you have not decided on. In my nanny app prototype there is a family selector that does nothing. It is there because I want to see people react to the idea of switching families. If someone says "I would never do that, I have only ever worked for one family", that is exactly what I wanted to learn.

Yes, a good prototype takes a while. It is nothing compared to the time you would waste building the thing without showing anyone first.

Proof of concept: can this be done?

A proof of concept exists to answer a technical or business feasibility question. Can this integration work. Can we get the data. Can the maths run fast enough. Can we deliver this at a price anyone would pay.

It is the one people misread, because a proof of concept that fails has succeeded. I have told a founder that their proof of concept proved the concept was not viable, and that this was a useful outcome: they found out cheaply instead of expensively.

MVP: the smallest thing you could actually release

I do not like calling something an MVP unless you are capable of releasing it. That is the line between this and the other two.

A true MVP is the minimum possible, which means it is usually enough to beta test with real users and not enough to hold them once it is in the store. That is fine, as long as you know that is the job it is doing.

The two in between, which are the most underrated

Concierge. You do the work by hand. Groupon did this: instead of an app where people found deals, the founders talked to people about the deals they wanted, went out and got them, and brought them back. Another company ran a WordPress blog with the founders reading emails and sending out PDFs of what was available that day, because building the real infrastructure would have been expensive. If people will not pay you to do it by hand, you will have a hard time getting them to pay for the app.

Wizard of Oz. People think they are using a product, and there is a person on the other side answering or driving the screens. Same thing, better disguise.

Both give you real evidence with no build, which is why they beat a prototype whenever money is the question.

Which one do I need?

• You are not sure people want this: prototype, and keep your idea out of the conversation until the end.
• You are not sure anyone will pay: concierge or Wizard of Oz, or a page with a price and nothing built behind it yet.
• You are not sure it can technically be done: proof of concept, and be willing for the answer to be no.
• You know all three and you want real usage: MVP, then work out what the lovable version adds.

What to watch when you put any of them in front of someone

Do they understand what it is for without being told? Do they get through the main task without real confusion? Did anything surprise them, well or badly? Did it address the problem you set out to solve?

Keep reading

What Is a Minimum Viable Product and Do I Actually Need One?

How to Validate a SaaS Idea Before Writing a Single Line of Code

How Do I Validate an App Idea Without Building It?

Learn this with me

Prototypes and proof of concept are class 6 of From Passion to Product, my free six-week live course, where you also learn low fidelity against high fidelity and which to use when. The MVP decision is later, in class 7, once you have a full feature list to cut down.

Knowing which of these three you need is a decision about what you are trying to find out, and both those weeks are about making that decision on purpose.

Join the waitlist for the next free cohort, or start with the App Strategy Workbook.