Runway's founder knew he had found product-market fit not just from revenue, but when a major customer, AngelList, began running its business on the platform and became an evangelist. Deep adoption by a respected company is a far stronger signal of PMF than early sales traction alone.

Many founders mistakenly define Product-Market Fit by revenue (e.g., "$1M ARR"). The correct measure is the ability to predictably create customer value. This is best quantified by a leading indicator for long-term retention, not sales figures, as revenue can be achieved without true market fit.

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.

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.

Founders often mistake $1M ARR for product-market fit. The real milestone is proven repeatability: a predictable way to find and win a specific customer profile who reliably renews and expands. This signal of a scalable business model typically emerges closer to the $5M-$10M ARR mark.

Sales are a vanity metric for product-market fit. The real test is having ~25 customers who have successfully implemented your product and achieved the specific ROI promised during the sales process. If you don't have this, you have a product problem, not a go-to-market problem.

PMF isn't a fixed state achieved once. It's a continuous process that must be re-evaluated at every stage of growth—from $1M to $1B. A company might have PMF for one scale but not for the next, requiring a constant evolution of strategy and product.

Having paying customers doesn't automatically mean you have strong product-market fit. The founder warns against this self-deception, describing their early traction as a "partial vacuum"—good enough to survive, but not to thrive. Being "ruthlessly honest" about this gap is critical for making necessary, company-defining pivots.

Founder Kyle Hanslovan saw the first signs of product-market fit at just $1.5M ARR. It wasn't about revenue scale, but the realization that the core business functions—demand generation, a fast sales cycle, and scalable service delivery—were becoming predictable, repeatable flywheels that could be systematically improved.