I've made a YNAB integration that automates the approach I've been using for managing multiple foreign currency accounts in a single budget. You can try it at fca4ynab.borsboom.io.

Some notable features of this integration that set it apart from other solutions (such using separate budgets for different currencies, or YNAB Multi-Currency):

• All your accounts, both local and foreign currency, are in a single budget so you can see the state of all your finances at a glance.

• Auto-import, manual import, and reconciliation for foreign currency accounts works normally, in the original foreign currency.

• Reports and net worth will always be shown in your local currency, with all foreign amounts converted at an exchange rate accurate to within 24 hours.

• Budget categories are in your local currency, and it's no problem to mix local and foreign currency transactions in the same budget category.

• Split transactions are converted correctly.

• Foreign currency balances are automatically adjusted as the currency fluctuates, at an exchange rate accurate to within 24 hours.

• Your original transactions left are untouched.

• Uses historical exchange rates for transactions in the past.

• Processes transactions continuously; you should see converted transactions within five minutes.

This is based on an approach that I've been using manually for several years and found to work very well for our family budget which crosses three different currencies and involves a lot of foreign transactions and transfers (after trying a few other ways first).

The approach boils down to:

• Transactions in foreign currency accounts are kept in their original foreign currencies, so imports and reconciliation work as they should.

• For each foreign currency in the budget, there is a "virtual" difference account that holds the difference between your total holdings in the foreign currency and your those holdings converted to your local currency.

• For each transaction in a foreign currency account, a corresponding transaction is created in the difference account with the difference between the foreign amount and the amount converted to your local currency (at the exchange rate of the day before the transaction's date).

• Adjustment transactions are created daily in the difference account to account for fluctuating exchange rates, with a special budget category used as a "buffer" for these fluctuations.

For example, if

• your local currency is U.S. Dollars
• you hold €100.00, and
• €1.00 = $1.10, then

the Euro difference account would hold $10.00, since

• €100.00 * $1.10/€1.00 = $110
• the difference ($110 - $100) is $10.

If you create a €10.00 transaction, a corresponding transaction for $1.00, with the same payee and category, will be created in the Euro difference account in order to keep its balance correct.

If this sounds helpful to you, please give it a try at fca4ynab.borsboom.io!