Takes prices that already include duties, taxes and/or fees and returns the underlying base price with those components stripped out, alongside an itemised breakdown of each component.

Use this where you display all-inclusive pricing to international shoppers but need the true base price for customs documentation.

The calculation is the exact inverse of the landed cost endpoint: the base price returned is the one whose forward landed cost reproduces the inclusive amount you submitted, so every rule the forward calculation applies (de minimis thresholds, customs unions, minimum and maximum measure-based duties, minimum collected duty, and low-value regimes) is honoured here too.

Notes:

• shipping_amount is not part of the inclusive amounts. It is charged separately to the shopper, but is included in the customs basis where the destination assesses duty on a CIF basis.
• Each line's components are rounded to two decimal places and the base price is derived as the remainder, so base_price + duty + sales tax + excise + additional taxes equals the inclusive amount you submitted exactly.
• Where an inclusive amount falls in the gap either side of a de minimis threshold, no base price can reproduce it. The base is then pinned to the highest value consistent with what customs will actually charge, and a note explains the shortfall.
• Each call consumes one reverse calculation credit. This is a separate monthly allowance from the landed cost one: check reverse_landed_cost in the /api/v1/usage response for what remains.