a lot of people smarter than me have written a lot of intelligent things about product market fit. i still get asked the question by entrepreneurs of how i would define it so i thought i'd lay down a summary of my thoughts here.
creative, but largely unhelpful definition:
where the rubber meets the road
or, as Andy Rachleff would say:
when the dogs start eating the dog food
this is the most simple definition. the market is ingesting what you're serving.
external (the investors) definition:
a non-trivial group of customers or users are engaging with your product and service, and have proven that they are willing to trade something valuable for it, usually time or money (or both)
internal (the founders) definition:
early observations of your original value hypothesis being proven correct. a value hypothesis articulates what exactly your product or service is, who will use it, and most importantly why they will value it.
when you have early signs that your product or service is being used by people who truly value it, you've achieved product market fit.
this framework may seem a bit at odds with lean startup methodology.
- what if the product or service that customers are valuing is not core to our business?
- what if my core product or service is being valued by customers we didn't built it for?
shouldn't these be celebrated? shouldn't that count as product market fit? yes, eventually. but in the first instance you need to rally the company around the product or service that is taking off, and potentially rethink your long-term mission, your medium term strategy and your short-term tactics. in the second instance you should run with it, but also ask yourself why your targeted audience isn't ingesting the product or service and another one is, and potentially rejig the customer facing aspects of your business accordingly.
the above definitions may seem vague and imprecise. the truth is, it's hard to find a universal definition of product market fit that applies to every company. it might mean 4 enterprise customers signing sizeable contracts, it might mean $80k MRR, it might mean participants in a network starting the share meaningful content with one another, it might mean one developer deploying your framework for the first time in production...
perhaps it's clear, but of the above, i think the internal definition is most vital. if you're confident you've achieved product market fit but an investor or external party doesn't agree, go find one that does.