Foreign exchange conversion is the exchange of value denominated in one currency for value denominated in another currency at an agreed or quoted exchange rate.
Cross-border payments can require foreign exchange at the payer side, recipient side, or an intermediate stage. A dollar stablecoin does not remove foreign-exchange exposure when the payer earns another currency or the recipient needs local currency. Providers can source FX through banks, market makers, exchanges, or automated liquidity venues and can quote the customer a rate that includes spreads and fees.
Foreign exchange conversion changes currency denomination. A stablecoin-to-dollar conversion can be fiat conversion without involving a change from one currency unit to another.
FX spreads and liquidity can be a large part of the total cost of cross-border stablecoin payments and can dominate the blockchain transaction fee.
A recipient who receives a dollar stablecoin but needs Swiss francs must ultimately exchange dollar-denominated value for francs.