In 2009, I lost a $2,000 sale at my glass studio because I couldn’t accept a credit card. That small failure started a chain of events I couldn’t have predicted.

I sat down with Guy Raz on How I Built This to tell that story in full: the unfiltered version. Not just the company-building mechanics, but the human stuff underneath it: the family trauma that rewired how I think, the seventeen regulations we violated to launch, the headphone jack hack that let us sidestep Apple, and the moment I realized we had product-market fit from the back of a cab.

The problem with the payments system

Most people assume the hardest part of building Square was the product. It wasn’t. The hard part was the system around the product: the regulations, the middlemen, the entrenched networks designed to keep outsiders out. Credit card processing in 2009 was a closed club. We were violating seventeen rules just by showing up.

The insight that unlocked everything was simple: the iPhone existed. It had a headphone jack. Audio signals are just voltage. If you could encode a credit card swipe as audio, you could process a payment on any phone without permission from anyone. That hack changed everything.

Why Amazon couldn’t copy us

When Amazon launched a competing product and undercut our price, most people assumed we were finished. We weren’t. What Amazon couldn't copy wasn't our card reader. They copied that exactly. What they couldn’t copy was our innovation stack: the interlocking set of novel solutions we had built to solve problems no one had solved before. Each innovation we made was individually copyable. Together, they were not. Less than a year after entering the market, Amazon was gone.

The pitch that won investors

We walked into investor meetings with a list of 140 reasons we might fail. I thought candor would be more convincing than confidence. It was. Investors had heard a thousand polished pitches. Nobody had ever handed them a list of everything that could go wrong. That honesty became its own signal.

The full episode is available on Wondery, Apple Podcasts, Spotify, and Amazon Music. It runs about an hour and ten minutes. Worth your time, if only to hear the part about the taxi.