How Retool Achieved Product-Market Fit: A Framework for Validating Assumptions and Building to 100 Happy Customers

David Hsu, founder of Retool, shares lessons from building an internal tools platform by testing hypotheses about target users and company size, iterating rapidly based on customer feedback, and discovering a massive market opportunity. The article demonstrates how standing firm on differentiated beliefs while systematically validating assumptions led to product-market fit, despite initial skepticism from peers and investors.