Product-market fit isn't a sudden switch but a palpable shift in momentum. As a founder, you feel the change from pushing against the current (hard selling with little traction) to suddenly being pulled by it (easier sales, inbound interest). This directional change in velocity is the clearest signal that you're onto something.

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.

For Ethic, the feeling of true product-market fit wasn't just hitting metrics, but the moment they helped an advisor win a major new client. The founder realized this success was a replicable playbook that could be repeated, creating a flywheel for growth. The metrics then followed this initial breakthrough.

The idea that startups find product-market fit and then simply scale is a myth. Great companies like Microsoft and Google continuously evolve and reinvent themselves. Lasting success requires ongoing adaptation, not resting on an initial achievement.

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.

Unlike traditional software where PMF is a stable milestone, in the rapidly evolving AI space, it's a "treadmill." Customer expectations and technological capabilities shift weekly, forcing even nine-figure revenue companies to constantly re-validate and recapture their market fit to survive.

Founders must distinguish between persistence and fighting a losing battle. If you constantly feel like you're pushing a boulder uphill to convince the market, you're on the wrong path. Genuine product-market fit feels like the market is pulling you, and your job is to sprint to keep up.

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.