Product-Market Fit (PMF)

Marc Andreessen famously described product-market fit as being in a good market with a product that can satisfy that market. The concept sounds simple, but achieving PMF is the single hardest challenge most startups face. Signals of PMF include organic word-of-mouth growth, high retention rates, short sales cycles, strong NPS scores, and customers who express genuine disappointment at the idea of the product disappearing. Sean Ellis popularized a quantitative test: if more than 40% of surveyed users say they would be very disappointed without your product, you likely have PMF. PMF is not a binary state but rather a spectrum that can strengthen or weaken over time as markets evolve and competitors emerge. Many SaaS companies achieve initial PMF with a specific segment and then need to find PMF again as they move upmarket or expand to new use cases. The search for PMF should drive every decision in the early stages: which features to build, which customers to target, and how to position the product. Once PMF is established, the focus shifts to building a repeatable and scalable go-to-market engine around it.