Tax summary webhook and calculation requests now includes shop and presentment currency amount

As of API version 2026-01, the tax_summaries/create webhook and tax calculation requests for Tax Partner Apps include additional fields for currency. These fields provide amounts in both shop currency and presentment currency. This enhancement allows tax partners to perform calculations and reporting in the merchant's accounting currency while maintaining the customer-facing currency for display.

What's New

The webhook and tax calculation request payloads now include two new currency-specific fields in the following locations:

1. Sale Records (agreements[].sales[]):

   • amount_before_taxes_after_discounts_currencies: A MoneyBag object containing the sale amount before taxes in both shop currency and presentment currency.

2. Cart Line Costs (delivery_groups[].cart_lines[].cost):

   • amount_per_quantity_currencies: A MoneyBag object containing the per-unit cost in both shop currency and presentment currency.

These fields complement the existing single-currency amount fields and are available when shops have multi-currency enabled.

MoneyBag Structure

The new MoneyBag fields contain two MoneyV2. Below is an example of the structure:

Before (2025-10 and earlier):

{
    "amount_before_taxes_after_discounts": {
        "currency_code": "CAD",
        "amount": "135.00"
    }
}

After (2026-01):

{
    "amount_before_taxes_after_discounts": {
        "currency_code": "CAD",
        "amount": "135.00"
    },
    "amount_before_taxes_after_discounts_currencies": {
        "shop_currency": {
            "currency_code": "USD",
            "amount": "100.00"
        },
        "presentment_currency": {
            "currency_code": "CAD",
            "amount": "135.00"
        }
    }
}