These three terms get used interchangeably, and the confusion costs founders real money — either building too much too early, or too little to learn anything. At our UK app and SaaS development studio we get asked to build all three, so here is the plain-English difference, when each makes sense, and what each typically costs.
Proof of concept (POC): can it be built?
A proof of concept tests feasibility. It exists to answer a single technical question: is this actually possible with the technology available? A POC is usually rough, internal-only, and throwaway. Nobody outside the team ever sees it.
You need a POC when there is genuine technical risk — for example, “can we process this volume of data in real time?” or “can we integrate with this legacy hospital system?” If your idea is a fairly standard app, you probably don’t need one; the feasibility is already known.
Prototype: how should it look and feel?
A prototype tests experience and design. It is usually a clickable mockup — screens linked together so you can walk through the flow — with little or no real code behind it. Nothing is actually functional; it just looks and behaves enough like the real thing to gather feedback.
Prototypes are excellent for testing user journeys, pitching to stakeholders, and refining the design before you spend money building. They are cheaper than an MVP because there is no working backend, no real data, and no production code.
MVP: will people use and pay for it?
A minimum viable product tests the market. Unlike the first two, an MVP is a real, working product — just built with the smallest set of features that delivers genuine value. Real users use it, and you learn from their behaviour, not their opinions.
The MVP is where most startups should focus, because it is the only one of the three that produces real customers, real revenue and real evidence. For a deeper look, see our MVP development guide and the case for why startups fail without an MVP.
Side-by-side comparison
| Proof of Concept | Prototype | MVP | |
|---|---|---|---|
| Question it answers | Can it be built? | How should it feel? | Will people use it? |
| Functional? | Partly (one risky bit) | No (clickable only) | Yes, real product |
| Real users? | No, internal | Test users | Yes, paying users |
| Typical cost | Low, narrow scope | Low–medium | From £5,000 |
| Outcome | Thrown away | Informs the build | Becomes the product |
Which one do you actually need?
- Standard idea, keen to test the market? Go straight to an MVP. This is most startups.
- Serious technical unknown? Do a small POC first to retire the risk, then build the MVP.
- Design-led product or need to pitch first? A prototype gets you feedback and buy-in cheaply before committing to the build.
- Want to be efficient? Combine a quick prototype (to lock the experience) with an MVP build (to ship it). That is how we run most engagements.
Whichever route fits, the goal is the same: spend the least money necessary to learn the most important thing. Before any of them, it is worth validating the idea with real potential users. When you are ready to put numbers to it, the MVP cost calculator gives an instant estimate, and we can build a focused MVP in around 21 days.
Frequently asked questions
Is a prototype the same as an MVP?
No. A prototype only looks and clicks like the product — there is no working code or real data behind it. An MVP is a real, functioning product that real users can actually use and pay for. A prototype informs the MVP; it does not replace it.
Can a proof of concept become the product?
It shouldn’t. A POC is built to answer one question quickly, not to be maintainable or scalable. Trying to grow a business on top of throwaway POC code is a common and expensive mistake — build the MVP properly once feasibility is confirmed.
The bottom line
Proof of concept, prototype and MVP are three different tools for three different questions — feasibility, experience, and market. Most founders overthink this and should simply build a well-scoped MVP, adding a POC or prototype only when there is a specific reason to. If you’re not sure which your idea needs, that is a five-minute conversation we’re happy to have on a free discovery call.