How to get per-line item price before discounts in Checkout UI extensions?

Extensions
1

I’m building a Checkout UI extension and need to send line item prices before any discounts are applied, exactly as they appear in the checkout UI (e.g. 749.95, 699.95, 629.95).

From the Checkout API I’m using:

  • api.cost.subtotalAmount → gives me the correct cart subtotal before discounts.

  • api.cost.totalAmount → cart total after discounts.

  • For each CartLine:

    • line.cost.totalAmount is present (line total after discounts),

    • but line.cost.subtotalAmount is undefined,

    • and line.merchandise.price is also undefined in this context.

So right now the only per-line amount I can reliably get is line.cost.totalAmount / quantity, which is the discounted per-unit price (e.g. 747.79, 697.935, 628.14), not the original prices shown in the UI.

Question:
Is there any supported way in Checkout UI extensions to access the original per-line item price before discounts (the same value the buyer sees as the product price), or do we have to fetch it ourselves via Storefront/Admin API using the variant IDs? If this is not currently exposed, is it planned to be added to the Checkout UI extensions API (e.g., a line.cost.originalAmount or line.merchandise.price field)?

2

Hi @Ammaar_Farhan_Syed

This looks like a current limitation of the Checkout UI Extensions API. Looking at the CartLineCost type in checkout extensions, it only exposes totalAmount — which is the post-discount total for the line. Fields like amountPerQuantity , subtotalAmount , and compareAtAmountPerQuantity that exist on the Storefront API’s CartLineCost are not currently available in the checkout extensions context.

3

@Liam-Shopify Can i use admin grapghQL query to fetch pre-discounted line amount ?

4

How is it possible to not have the original price of line items?

I need them to calculate a promotion and it’s unbelievable I can’t get a field that’s available everywhere but the checkout