A proof of concept proves that something technical can be done, is seen by your own team, costs $5,000 to $25,000 (€4,500 to €22,000, £3,500 to £18,000) and is thrown away. A prototype shows what the product will be like, is seen by users and investors, costs $5,000 to $50,000 (€4,500 to €44,000, £3,500 to £37,000) depending on whether it is clickable or functional, and is mostly replaced. An MVP is a real product that real users rely on, costs $20,000 to $80,000 (€17,000 to €70,000, £15,000 to £60,000), is measured for retention, and is built on. Most products need a prototype and an MVP. Only products with a genuine technical unknown need a proof of concept first.
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Founders use these three terms interchangeably, agencies use them to mean whatever they are selling, and investors use them to mean "show me something". They are three different things, built for three different audiences, and building the wrong one wastes months. This post compares them on what matters, says which order to build them in, and names the cases where you can skip one.
What is the difference?
| Proof of concept | Prototype | MVP | |
|---|---|---|---|
| Question it answers | Can this be done? | What will it be like? | Will people use it and come back? |
| Who sees it | Your team, maybe a technical investor | Target users in testing, investors, early partners | Real users, in their own lives |
| What it contains | The one hard technical thing, with no interface worth the name | Clickable: designed screens linked together. Functional: one working journey with real data | The complete core journey, accounts, basic admin, analytics, on one platform |
| What it proves | Technical feasibility | Desirability and usability, and that you can define a product | Demand and retention |
| Cost | $5,000 to $25,000 (€4,500 to €22,000, £3,500 to £18,000) | Clickable $5,000 to $15,000 (€4,500 to €13,000, £3,500 to £11,000). Functional $15,000 to $50,000 (€13,000 to €44,000, £11,000 to £37,000) | $20,000 to $80,000 (€17,000 to €70,000, £15,000 to £60,000) |
| Time | 1 to 4 weeks | Clickable 2 to 4 weeks. Functional 4 to 8 weeks | 8 to 16 weeks |
| What happens to it | Thrown away | Clickable: replaced by the real product. Functional: often becomes the core of the MVP | Built on, measured, becomes the product |
| Measured by | Does it work on real inputs? | Do test users complete the journey? Do investors lean in? | Activation and retention |
When do you need a proof of concept?
Only when there is a real technical unknown: a model that needs to reach a certain accuracy on your data, a device that needs to talk to your software, an integration with a system nobody has documented, a performance requirement nobody has met. The proof of concept answers that one question in the cheapest possible way, with no interface and no product around it. If the answer is no, you have saved the whole build. If it is yes, the code is usually thrown away and the real thing built properly. Most products have no technical unknown and need no proof of concept. A team proposing one for a standard web or mobile product is padding the project.
When do you need a prototype?
Almost always, and it is the cheapest step with the highest return. A clickable prototype, which is the designed screens linked so a user can tap through the core journey, catches most usability problems before anything is built, gives investors something to touch, and makes the scope concrete enough to quote. It is built in the design phase of every MVP we do. Wireframe, mockup and prototype explains the design artefacts.
A functional prototype, which is one real working journey with a real backend and often one real integration, is a bigger step. You need one when investors or partners need to see the thing actually work, when a hard integration must be proven alongside the user experience, or when the Startupper route of prototype-then-funding-then-MVP fits your capital. What is a functional prototype covers it, and how to raise money with only a prototype covers using one to fund the MVP.
When do you need an MVP?
When the question is whether users want the product enough to come back, and that question cannot be answered by a prototype, because a prototype is used in a test session and an MVP is used in a life. An MVP is a real product: the core journey complete and reliable, accounts, enough admin to run it, analytics on every step, on one platform. It is what you build once the problem is validated and the product is designed. What an MVP is and what to leave out covers the scope, and our complete guide to MVP development covers the whole path.
What order do you build them in?
- Validation without building. Interviews, landing page, concierge. Before any of the three.
- Proof of concept, only if there is a technical unknown. One to four weeks.
- Clickable prototype. Two to four weeks, tested with ten target users. Part of MVP design.
- Functional prototype, if you need to raise or prove an integration before the full MVP. Four to eight weeks. Skip it if you have the capital to go straight to the MVP.
- MVP. Eight to sixteen weeks. Measured for 90 days.
Most products do steps one, three and five. Products with technical risk add step two. Products that need to raise before the MVP add step four.
What are the common confusions?
- Calling a prototype an MVP. A clickable prototype shown to investors as "our MVP" is fine as a pitch. Treating it as proof of demand is not. Nobody has relied on it.
- Calling an MVP a prototype. A team that builds a real product with accounts and payments and calls it a prototype has either under-priced it or will treat it as throwaway. Neither is good.
- Building a proof of concept with an interface. If it has screens and a login, it is a prototype, and it cost three times what the technical question needed.
- Launching a functional prototype as the product. It has one journey and no admin, analytics or error handling. It will fail in ways that tell you nothing about demand.
Which do you need?
- Technical unknown: proof of concept, then the rest.
- Need to test the experience or raise a small round: clickable prototype.
- Need to show it working to investors or partners before the full build: functional prototype.
- Need to know whether users come back: MVP.
How 7L sequences them
The Startupper Program runs vision and validation, functional prototype, MVP, market entry and scale, in that order, and a founder can enter at whichever phase their evidence supports. A clickable prototype is inside every MVP design phase. A proof of concept is proposed only when we can name the technical question it answers. If you are not sure which of the three you need, tell us what you are trying to prove and to whom, and we will tell you which one proves it.
Frequently asked questions
Can a prototype become the MVP?
A clickable prototype cannot, since it has no working code. A functional prototype often does: the working journey becomes the core of the MVP if it was built on a sensible stack with a sensible data model. Ask the team at the start whether the prototype is meant to be built on or thrown away, and price accordingly.
Do investors want a prototype or an MVP?
At pre-seed, a prototype with evidence of demand such as a waiting list or letters of intent is usually enough. At seed, most investors want an MVP with retention data. Our post on what investors want to see in your tech before seed covers what they check.
Is a proof of concept the same as a pilot?
No. A proof of concept tests whether something can be done technically, inside your team. A pilot is a real customer using a working product for a defined period, which is closer to an MVP with one customer. Pilots are common in B2B and are covered in our B2B MVP post.
How much of the MVP cost does a prototype save?
A clickable prototype saves far more than it costs by catching usability problems before development, typically weeks of rework. A functional prototype does not save MVP cost so much as spread it, since its code becomes part of the MVP. Neither is wasted if built for the right reason.
Can I skip the prototype and go straight to an MVP?
You can skip the functional prototype if you have the capital and no integration to prove. You should not skip the clickable prototype. It is two to four weeks inside the design phase and it is the cheapest point at which to find out the first session does not work.