The founder realized he had product-market fit not from praise, but from anger. When the system went down, his few early customers were furious because they had come to rely on it, even in its imperfect state. This is a powerful, non-obvious signal of true customer dependency.

Metrics can be misleading. The founder's true "aha" moment for product-market fit came from solving a complex, real-world problem posed by a skeptical expert during a live demo. When the product solved in seconds what took the customer's team two weeks, it provided undeniable proof of value in a high-stakes environment.

When a product addresses a significant need, early adopters will actively help you fix bugs and overcome hurdles. This intense engagement, despite product immaturity, is a powerful indicator of product-market fit. Users are willing to go "above and beyond" because the outcome is so valuable to them.

This visceral analogy reframes product-market fit as an uncontrollable, overwhelming demand from the market. It's not just positive metrics; it's a state of being swarmed by customers. If you don't feel this intense 'market pull,' you haven't truly achieved it and must keep iterating.

Product-market fit isn't just growth; it's an extreme market pull where customers buy your product despite its imperfections. The ultimate signal is when deals close quickly and repeatedly, with users happily ignoring missing features because the core value proposition is so urgent and compelling.

The ultimate test of PMF isn't surveys or usage metrics, but how indispensable your product is. If customers don't immediately notice and complain when it's gone, you haven't achieved true dependency. It's a visceral, high-signal test for any founder.

You've achieved product-market fit when the market pulls you forward, characterized by growth driven entirely by organic referrals. If your customers are so passionate that they do the selling for you, you've moved beyond just a good idea.

Hux's founder measures success not just by retention, but by the passion of retained users. When users start writing in daily, angrily demanding bug fixes, it's a strong positive signal. It means the product has become so essential to their routine that they care deeply about its improvement.

In the early days, Canary's pitch received mixed reactions. However, the strong, visceral "I need this now" response from a few customers was a more valuable signal of product-market fit than getting a polite "that's cool" from everyone. This validates the "10 true fans" principle in B2B.