FX Swaps market

The swaps market is where financial institutions exchange swaps. An FX swap is an agreement between two foreign parties to swap interest payments on a loan made in one currency for interest payments on a loan made in another currency.

A foreign currency swap can involve exchanging principal, as well. This would be exchanged back when the agreement ends. Usually, though, a swap involves notional principal that's just used to calculate interest and isn't actually exchanged.