There’s a gap in how we talk about building products. I’ve been thinking about it for a while, and I think it comes down to a missing stage - one that sits right between shipping something and committing to it.
The lean startup vocabulary gives us MVP. Build the smallest thing that works, ship it, learn. Then eventually, if you’re lucky, you reach PMF - Product-Market Fit. The moment the market pulls the product out of your hands.
But what happens in between? You have a working prototype. Now what?
The leap most people miss
The standard playbook goes: MVP → launch → iterate → PMF. Implicit in this is the assumption that you should keep building after the MVP. That iteration is always the right move. That adding features will eventually unlock demand.
I don’t think that’s true. I think the leap from MVP to PMF is where most projects actually die, and it’s not because the product was bad. It’s because there was never a clear signal that the market wanted it in the first place. The MVP proved you could build it. But building is cheap now.
What’s expensive is deciding to keep building.
vibecoding changed the math
A few years ago, the hard decision was whether to build at all. MVPs took time, money, engineers. So validating demand before building made sense - that’s what people call a Minimally Viable Market. Talk to users, understand their pain, confirm they’d pay. Then build.
But with vibecoding, the cost of building an MVP dropped to almost zero. You can describe something to an AI and have a working prototype in hours. So the constraint shifted. It’s no longer “can I build this?” It’s “should I keep building this?”
That’s a fundamentally different question. And it needs a different checkpoint.
Minimum Market Fit
I’ve been calling it Minimum Market Fit, or MMF. It’s the earliest point where you have real evidence that the product you built - not just the idea, but the actual thing in someone’s hands - has demand.
Real evidence means something specific. Not vanity metrics. Not “people said they liked it.” Not signups from your own network. I’m talking about:
- Someone you don’t know found it and used it more than once
- Organic retention - they came back without you prompting them
- A willingness to pay, or at least a clear signal that they’d be upset if it disappeared
MMF is not PMF. You don’t need explosive growth or a clear monetization model. You just need signal. The quiet, unambiguous kind that says: this solves a real problem for a real person.
The three stages, clearly
So here’s how I think about the pipeline now:
Minimally Viable Market - validate demand before building. Understand who has the problem, how intense it is, and whether they’d pay to solve it. The Mom Test by Rob Fitzpatrick is a good methodology for this part.
Minimum Viable Product - build the smallest thing that addresses the problem. With vibecoding, this is almost free. It’s a prototype, a v0, a rough draft. It doesn’t need to be pretty. It needs to work.
Minimum Market Fit - the checkpoint. Put the MVP in front of real people and watch. Does anyone care? Not in the abstract, but concretely. Do they use it? Do they come back? Do they tell someone else?
If yes - you have MMF. Now invest. Keep building. Iterate. Move toward PMF.
If no - stop. Not forever. But stop pouring energy into something that hasn’t earned it yet. Go back to the MVM stage. Talk to different people. Maybe the problem isn’t what you thought it was.
Why this matters
I think a lot of founders confuse motion with progress. They ship an MVP, get a few polite compliments, and interpret that as permission to keep going. Six months later they’re exhausted, the product has more features but the same number of users, and they can’t tell if they’re close to something or wasting their time.
MMF gives you a clean decision point. It doesn’t tell you what to build or how to build it. It tells you whether the thing you built is worth continuing.
I don’t know if this framing is new. The idea - that you need real demand signal before committing resources - is well understood implicitly. Marc Andreessen wrote about PMF in 2007. Y Combinator’s “do things that don’t scale” is about finding this moment. Rob Fitzpatrick’s whole book is about getting honest signal before you build.
But I’ve never seen it named as a formal stage gate. It’s always been implied, buried inside the vague space between MVP and PMF. And I think giving it a name makes it actionable.
So that’s what I’m doing. Minimum Market Fit. The point where you know - quietly, concretely - that someone actually wants the thing you built.
Everything before that is a guess. Everything after is an investment.
