Gemini is a cryptocurrency exchange and custodian that allows customers to buy, sell, and store digital assets. It was founded in 2014 by Cameron and Tyler Winklevoss. The company is headquartered in New York City and is regulated by the New York State Department of Financial Services. Gemini offers a variety of services including trading, custody, and market data APIs. The exchange supports a number of cryptocurrencies including Bitcoin, Ethereum, and Litecoin.