Somewhere in 2017, David Hsu was watching $1,000 drain out of his fintech startup every single day. Cashew - a peer-to-peer payments app he'd built after a friend couldn't pay him back for ice cream in England - was in its final 60 days of runway. Rather than scrambling to save it, Hsu noticed something: he kept building the same software over and over. Tables. Buttons. Dropdowns. Fraud dashboards. Admin panels. The same components, assembled from scratch, every time.
Within days of that realization, he had a prototype. Within months, he was at Y Combinator Demo Day with a signed $1.5 million enterprise pilot. Within five years, he'd built Retool into a $3.2 billion company used by Amazon, Netflix, OpenAI, and the US Army - all from the fundamental insight that internal software was boring, repetitive, and could be fixed with a drag-and-drop interface.
Retool is not a household name the way Slack or Figma is. It doesn't need to be. Every time a DoorDash operations manager spins up a custom dashboard, or a hospital admin builds a patient intake tool without writing a line of CSS, Retool is the invisible infrastructure. More than 10,000 companies have now replaced entire engineering sprints with an afternoon in Retool.
Hsu studied Computer Science and Philosophy at Oxford - an unusual combination that he wears less as a credential and more as a lens. When he describes Retool's approach to product-market fit, he talks in terms of hypotheses, falsifiability, customer conversations as evidence. The philosopher's move: never assume you're right, keep looking for reasons you might be wrong.
It was this mindset that saved Retool's early trajectory. After Demo Day, the first instinct was to target FileMaker developers and small startups - a hypothesis that didn't pan out. The evidence pointed elsewhere: frontend and backend developers at mid-size enterprises managing real software budgets. Hsu pivoted the targeting, rewrote the outreach, and hit $2 million ARR before any public launch or press coverage.