Multi-Currency & FX — Payments & Money APIs

Selling internationally distinguishes presentment currency (what the customer sees and pays) from settlement currency (what you receive). Options: price natively per currency (best conversion), let the PSP convert at settlement (FX fee), or hold balances in multiple currencies. Store the original amount and currency, the settlement amount, and the FX rate and source used. Refunds in the presentment currency can settle at a different rate — your ledger needs an FX gain/loss account.

Multi-currency strategies

Approach	Customer experience	Your FX exposure	Complexity
Single currency (e.g. USD only)	Card issuer converts (fees, surprises)	None	Lowest
Local prices, PSP converts to settlement currency	Good	Rate at settlement	Medium
Local prices, multi-currency balances	Good	Managed by you	High
Dynamic currency conversion at checkout	Mixed (often poor rates)	Low	Medium

Stored payment record

{
  "payment_id": "pay_81",
  "presentment": {"amount_minor": 4999, "currency": "EUR"},
  "settlement": {"amount_minor": 5381, "currency": "USD"},
  "fx": {"rate": "1.07641", "source": "psp", "captured_at": "2026-10-11T09:20:00Z"},
  "fees": {"amount_minor": 186, "currency": "USD"}
}

Common pitfalls

Storing only converted amounts.
Using a live FX rate to refund a past payment in the settlement currency.
Rounding converted amounts inconsistently.

Key points

Keep presentment + settlement + rate
FX gain/loss in the ledger
Price natively where it matters

Further reading: Stripe: Currency conversions

Practice questions

What's the difference between presentment and settlement currency?

Answer

Presentment is what the customer is charged in; settlement is the currency the merchant receives after any conversion.

Why can a full refund of a foreign-currency payment cost you money?

Answer

The refund is converted at the rate on the refund date, which may differ from the original rate, creating an FX loss (or gain).