Before 21 Inc. had even put out a product, it had raised $121 million in venture funding—the most of any bitcoin company. It was unclear, for months, what 21 would actually do or make. But some of the biggest names in fintech funding, including Andreessen Horowitz, Khosla Ventures, and the Winklevoss brothers, were interested enough to invest.
Then things started to move very quickly. In February, 21 released its first product—and it was hardware, a rarity among bitcoin companies. It was the 21 bitcoin computer, which allows for mining the cryptocurrency as well as building applications on top of the bitcoin blockchain, the open-source, decentralized ledger that underlies bitcoin.
The computer, which runs on Raspberry Pi (a small, single-board programming computer launched in 2012), sells for $400 and is about the length of an iPhone. It attracted a lot of buzz and attention in the bitcoin world.