Note that they guarantee the exchange rate, assuming the transaction is eventually confirmed. https://support.bitpay.com/hc/en-us/articles/115002990823-How-do-I

Note that they guarantee the exchange rate, assuming the transaction is eventually confirmed. https://support.bitpay.com/hc/en-us/articles/115002990823-How-do-I-prevent-double-spend-fraud-on-unconfirmed-payments- https://support.bitpay.com/hc/en-us/articles/115002990823-Ho...