How do I accept payments in multiple currencies with one API?

To accept payments in multiple currencies with one API, you typically use a payment gateway/processor that supports multi-currency processing. The general approach looks like this:

1. Use a PSP that supports multi-currency

Examples include Stripe, Adyen, PayPal, Braintree, Worldpay, etc. They let you create charges/payment intents in different currencies through a single integration.

2. Decide how you want to handle currency

Common options:

• Presentment currency: Charge the customer in their local currency.
• Settlement currency: Receive funds in one base currency, with conversion handled by the provider or your bank.
• Multi-currency balances/accounts: Hold balances in several currencies and settle separately.

3. Send the currency with each payment request

Most APIs accept an ISO 4217 currency code like:

• USD
• EUR
• GBP
• JPY

Example conceptually:

{
  "amount": 4999,
  "currency": "EUR"
}

4. Add currency selection logic

Your app can:

• Detect user locale/IP (carefully)
• Let users manually choose currency
• Use the billing/shipping country to suggest a currency
• Apply your own FX rate if needed

5. Make sure your backend supports currency-specific amounts

Important:

• Amounts are usually sent in the smallest unit (cents, pence, yen depending on currency rules)
• Some currencies have no decimals (like JPY)
• Conversion rates, rounding, and taxes need careful handling

6. Handle refunds and disputes in the same currency

Refunds are usually processed in the original transaction currency, so store:

• transaction ID
• currency
• original amount
• exchange rate if you converted internally

7. Check compliance and local requirements

Depending on countries/currencies, you may need:

• Local acquiring
• 3D Secure / SCA in Europe
• Tax/VAT handling
• Country-specific payment methods

Typical architecture

• Frontend: customer selects currency
• Backend: creates payment intent/charge with amount + currency
• PSP: processes payment and settles according to your account settings
• Webhooks: confirm payment status and update your order

If you want the simplest solution

Choose a provider that offers:

• One unified API
• Multi-currency acceptance
• Automatic currency conversion
• Webhooks and refunds support

If you want, I can show you:

1. a Stripe example,
2. an Adyen example, or
3. a generic backend design for multi-currency payments.