Kraken is a popular cryptocurrency exchange that charges fees for its trading services. The fees vary based on the amount of trades made, but they are generally lower than those charged by other exchanges. Kraken also offers a variety of other features, such as margin trading and a wide selection of altcoins.

Website: https://www.kraken.com

Fees: https://www.kraken.com/en-us/help/fees

Twitter: https://twitter.com/krakenfx