Which startup was founded by Brian Armstrong?

Brian Armstrong founded Coinbase.

Armstrong founded Coinbase in June 2012 after working as an engineer at Airbnb. He entered the startup through Y Combinator, which provided a $150,000 investment. The original idea was to make it easier for people to buy and use bitcoin, especially through bank transfers rather than technically demanding cryptocurrency tools.

Fred Ehrsam later joined Armstrong as a co-founder after discovering Armstrong’s work online. Coinbase began offering bitcoin buying and selling through bank transfers in October 2012, helping establish it as a consumer-facing gateway to cryptocurrency. The company eventually expanded into trading, custody, staking, and other digital-asset services.

A historical nuance is that British programmer Ben Reeves was initially expected to be part of the founding team, but he and Armstrong split over how the wallet should operate. Coinbase is commonly described as founded by Armstrong and Ehrsam, while Armstrong remains its best-known founder and long-serving CEO. Gemini, Kraken, and Binance are competing cryptocurrency platforms, not the startup Armstrong founded.