Article · about 15 min read

How to Know If You've Got Product-Market Fit

Lenny Rachitsky · Lenny's Newsletter Freemium Intermediate

Once you are testing an idea, this piece gives you concrete signals that tell you whether it is actually working, from retention curves to organic word of mouth. It collects how experienced founders and investors describe the moment an idea starts to land. Read it so you know what evidence to look for instead of guessing whether the idea is good.

  • Retention that flattens rather than falling to zero is the clearest signal
  • Organic growth and referrals show the problem was real
  • If people would be very disappointed to lose it, you are onto something
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It answers 11 questions

  1. How do I know if my idea is any good?
  2. My first 5 customers were friends who signed up to be nice. How do I know if any of them actually want the product?
  3. How do I know if I've found product-market fit?
  4. When should I pivot vs. persevere?
  5. My co-founder and I keep debating two ideas and cannot agree, how do we decide?
  6. How do I stop myself from adding features nobody asked for just because I enjoy building?
  7. What are the warning signs a developer is building the wrong thing?
  8. What are the most common mistakes founders make when they try to build on a hot trend?
  9. How do I actually measure whether a launch worked, beyond the vanity upvotes and traffic spike?
  10. What are the warning signs that an idea will quietly waste a year of my life?
  11. How do I know when I've validated enough to actually start building?

Read with it

  1. Turns the vague feeling of product-market fit into a number you can move. Ask users how they would feel if they could no longer... First Round Review Article · ~20 min read How Superhuman Built an Engine to Find Product/Market Fit Rahul Vohra
  2. The single best thing ever written on customer conversations. It teaches you to ask about the customer's life and past... momtestbook.com Book · ~130 pages The Mom Test Rob Fitzpatrick
  3. The definitive essay on where good ideas come from: notice problems you personally have, don't force it. Use it as the lens for... paulgraham.com Essay · ~20 min read How to Get Startup Ideas Paul Graham
  4. The essay that put 'product-market fit' into the startup vocabulary. Read it for the gut-level description of what PMF feels... pmarchive.com Essay · ~15 min read The Only Thing That Matters Marc Andreessen
  5. Video · ~25 min How to Talk to Users Eric Migicovsky
  6. Video · ~50 min How to Evaluate Startup Ideas Kevin Hale, Y Combinator
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