Forex (FX) is the abbreviation of foreign exchange (exchange). When trading with Forex, two currencies are exchanged against each other: The purchase of one currency leads to the simultaneous sale of another. Currencies are always traded in pairs, which is why they are also called currency pairs. The FX trading market - the largest financial market in the world - is often referred to as the foreign exchange market or currency market. Learn how to trade forex via CFDs with leverage in this free guide! How does Forex trading work? In currency trading, individual clients, businesses, and organizations trade or exchange different currencies around the world. In currency trading, the first currency in the pair is called the base currency and the second currency is called the quote currency. As a trader, you speculate on the evolution of the exchange rate: Is the exchange rate of one country's currency rising or falling against another country's currency? We clearly explain the princ