BitTrex. A popular digital asset trading service. Bittrex is one of the larger crypto to crypto exchanges offerign a large number of trading pairs into bitcoin - including all the major cryptos such as darkcoin, nextcoin and litecoin. They also offer NeuCoin and Ethereum. Based in Seattle, Washington, the company was founded in 2013 by Bill Shihara and two business partners, who previously worked as security professionals at Microsoft.