Stefan Thomas

Stefan Thomas wrote a widely watched early Bitcoin explainer video and one of the first working implementations of Bitcoin’s cryptography for a web browser. He went on to become chief technology officer of one of Bitcoin’s biggest rivals, co-invent a payments protocol whose open-source infrastructure is still active in more than 40 countries, and found a company built to change how the web pays for itself. None of that is why most people who recognize his name know it. They know it because of a piece of paper he lost.

In 2010, Thomas discovered Bitcoin and began contributing to it as an unpaid open-source developer. He wrote BitcoinJS, one of the earliest working implementations of Bitcoin’s cryptography for a browser, and founded WeUseCoins.com, which grew into the largest information site for newcomers to Bitcoin at the time. Around the same period, working with a small team funded by a bounty the Bitcoin community itself had pooled together, he helped produce What is Bitcoin?, one of the first widely shared video answers to the question the currency’s own name kept raising. He was paid roughly 7,002 BTC for the work — and stored the wallet’s key on an IronKey encrypted USB drive whose password he later lost.

Before the lockout: BitcoinJS and “What is Bitcoin?” (2010–2011)

Thomas was not chasing an audience with WeUseCoins.com. In a BitcoinTalk interview from the site’s early days, he described deliberately steering away from mainstream marketing and toward specific communities that could actually put Bitcoin to use — an online gaming guild here, a paragliding operator he found through Bitcoin’s own trade forum there. BitcoinJS grew the same way: quietly. “I’m actually okay with it not being well known,” he said of the library at the time. “It’s still pretty young, so it’s good to have some time where I can fix bugs, rewrite stuff and generally let it mature while it isn’t used too widely.” The library became one of the first tools that let a website run Bitcoin’s cryptography directly in a browser, without a separate client — a building block other early JavaScript wallet projects built on.

Thomas turned the same habit of looking at the data on Satoshi himself. Wired’s 2011 feature reported that he graphed the time stamps of Satoshi’s 500-plus forum posts and found a steep decline to almost no posts between 5 a.m. and 11 a.m. Greenwich Mean Time, a pattern that held on weekends too. Chain Bulletin revisited the same approach in 2020 on a far larger set of records.

Ripple, Interledger, and Coil (2012–2023)

In 2012, Thomas joined Jed McCaleb’s newly formed OpenCoin — renamed Ripple Labs the following year — as chief technology officer, building the client software for what became the XRP Ledger and later leading work on smart contracts. The frustration that shaped his next project was older than Ripple itself: as a freelance web developer he had repeatedly run into friction moving small payments across borders to subcontractors and clients. His answer wasn’t another blockchain. In 2015, while still at Ripple, he co-created the Interledger Protocol, describing the goal plainly: “a protocol for routing packets of money just like the internet routes packets of data.”

In 2018 he left Ripple to found Coil, a startup that used Interledger to stream micropayments to websites in real time; David Schwartz, Ripple’s chief cryptographer since 2011, succeeded him as CTO. Coil shut down in early 2023 after roughly five years of operation — Thomas has continued the underlying work as chairperson of the Interledger Foundation and, more recently, as a contributor to Dassie, an open-source peer-to-peer implementation of the protocol.

The password he can’t remember

The 7,002 BTC Thomas was paid for the What is Bitcoin? video has been effectively frozen since he lost the paper carrying his IronKey’s master password. The device wipes itself after ten wrong guesses; as of the January 12, 2021 New York Times report that first drew wide attention to the story, eight had already been used. The full account of the lockout — the device’s design, the price swings that turned the stuck balance into hundreds of millions of dollars, and the 2023 recovery offer Thomas turned down — is recorded on its own page. As of 2026 the IronKey sits in a Swiss vault, unopened, with two guesses left and no confirmed path to recovering what’s inside.

Significance

Thomas spent the decade after losing that password building infrastructure for money that never touched Bitcoin again — a rival ledger, a routing protocol, a micropayments company — while the fortune he can’t reach sat exactly where he’d left it, growing more valuable every year he didn’t touch it. That isn’t irony so much as the plainest possible demonstration of what Bitcoin actually promises: not that you’ll never lose access, but that if you do, nothing and no one — not a company, not a court, not the person who wrote the code that locked it — can give it back. James Howells’s bitcoin, buried under a Welsh landfill instead of locked behind a forgotten password, makes the same point from the opposite direction: courts ruled on exactly who owned his drive, and it still didn’t get him his coins back. The seven thousand coins are still there. So is the reason no one, including Thomas, can move them.