A cryptocurrency exchange, or a digital currency exchange (DCE), is a business that allows customers to trade cryptocurrencies or digital currencies for other assets, such as conventional fiat money or other digital currencies. A cryptocurrency exchange can be a market maker that typically takes the bid–ask spreads as a transaction commission for is service or, as a matching platform, simply charges fees.
A decentralized exchange (DEX) is a cryptocurrency exchange which operates in a decentralized way, i.e., without a central authority. Decentralized exchanges allow peer-to-peer trading of cryptocurrencies. Because users do not need to transfer their assets to the exchange, decentralized exchanges reduce the risk of theft from hacking of exchanges. Decentralized exchanges can also prevent price manipulation or faked trading volume through wash trading, and are more anonymous than exchanges which implement know your customer requirements.