Product-Market Fit (PMF)

Also known as: PMFProduct Market FitMarket FitProduct-Market MatchProblem-Solution Fit

PMF Score = % of users who'd be 'very disappointed' without your product (target: ≥40%)

💡The Concept

Product-Market Fit is the degree to which your product satisfies a strong market demand. When you have PMF, customers are actively pulling your product from you rather than you pushing it onto them. Marc Andreessen defined it as 'being in a good market with a product that can satisfy that market.' The Sean Ellis test quantifies it: if 40%+ of users say they'd be 'very disappointed' without your product, you have PMF. Before PMF, nothing else matters — marketing spend is wasted, hiring is premature, and features are guesses. After PMF, everything gets easier: organic growth appears, retention improves, and word-of-mouth starts compounding.

⚠️The Trap

Founders declare PMF too early based on vanity metrics — sign-ups, press coverage, 'exciting conversations' with potential customers. True PMF means users would be genuinely disappointed if your product disappeared. The second trap: assuming PMF is binary and permanent. PMF exists on a spectrum and can erode as markets shift (Blackberry had PMF until iPhone changed the market). Also: PMF for one segment doesn't mean PMF for another — you might have PMF with startups but not enterprises.

🎯The Action

Run the Sean Ellis survey: ask existing users 'How would you feel if you could no longer use [product]?' with options: Very Disappointed, Somewhat Disappointed, Not Disappointed. If 40%+ say 'Very Disappointed,' you likely have PMF. If not, interview the disappointed users to learn what they love, and double down on that specific value. Track the PMF score quarterly — it should improve as you refine the product.

⚡Pro Tips

The best PMF indicator isn't the survey — it's organic growth. If users are referring others without being asked, that's PMF. If you have to bribe people with referral discounts, you probably don't have it yet.

PMF isn't just about the product — it's about the SEGMENT. Superhuman focused obsessively on one segment (high-volume emailers in venture capital) until they hit 58% 'very disappointed.' Only then did they expand to other segments. Focus creates PMF; breadth dilutes it.

Paul Graham's test: 'Do you have customers who are using your product and recommending it to others WITHOUT you asking?' If the answer is yes, you're approaching PMF. If no, keep iterating.

🚫Common Myths

✗Myth: “PMF means everyone loves your product”

✓Reality: PMF means a SPECIFIC group of people can't live without it. Slack didn't have universal PMF — many teams tried and abandoned it. But for engineering teams at startups, it was indispensable. You need fanatical love from a specific segment, not lukewarm appreciation from everyone.

✗Myth: “Once you achieve PMF, you've 'made it'”

✓Reality: PMF is not a permanent state. Markets change, competitors emerge, and customer needs evolve. Blackberry had extraordinary PMF until the iPhone. MySpace had PMF until Facebook. Maintaining PMF requires continuous product evolution. Measure it quarterly, not once.

📊Real-World Case Studies

✉️

Superhuman

2017-2020

success

Superhuman is the gold standard example of using the Sean Ellis test to methodically achieve PMF. CEO Rahul Vohra surveyed early users and found only 22% would be 'very disappointed' — well below the 40% threshold. Instead of guessing, he segmented responses and found that venture capitalists and startup founders scored 42%. He narrowed focus to that segment, built features they specifically requested, and tracked the score monthly. It rose from 22% to 33% to 58% over 6 months. Superhuman then expanded from this beachhead.

Initial PMF Score

22%

Target Segment PMF Score

42%

Final PMF Score (after iteration)

58%

Time from 22% → 58%

~6 months

💡 Lesson: Superhuman proved that PMF is not found — it's built. By measuring PMF quantitatively, segmenting to find the highest-fit users, and building specifically for them, any company can systematically improve their PMF score. The key insight: don't try to please everyone. Find your 'very disappointed' segment and go all-in.

Source →

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Scenario Challenge

You survey 200 users. 50 say 'very disappointed,' 80 say 'somewhat disappointed,' and 70 say 'not disappointed.' Your team wants to start scaling marketing.

🧪 Challenge a Friend