Kraken is a veteran US based cryptocurrency exchange that supplies an advanced trading platform complete with margin trading and OTC options. Previously scorned for the platform’s instability, the site has since revamped its service with a focus on security and customer support. They also have a low minimum account balance requirement. Kraken is currently available to almost all countries, with a handful of exceptions. The support structure has been a point of concern for many traders. While slow in general, they do offer a FAQ and support section to their website. Kraken’s fees are among the lowest of all the major bitcoin exchanges. The fees you pay depend on your last 30 days’ trading volume. Because of a complex interface, and a slightly less than stable platform, it is not recommended for new traders.