You’ll need a few details to send or receive a transfer – either domestically or internationally.
IBANs (international bank account numbers) identify individual bank accounts. They're issued by many banks in Europe, but banks elsewhere in the world are starting to adopt them as well.
Routing numbers help identify banks when processing domestic ACH payments or wire transfers. But only in the United States. You don't need one to make a payment to your friend in France, for example.
SWIFT codes, like routing numbers, also identify banks and financial institutions. This time for international payments. They're sometimes known as BIC codes.