Create a Shopify discountAutomaticBxgy (buy X get Y) discount via Admin GraphQL

In-depth guide

Steps

1. Use the discountAutomaticBxgyCreate mutation with a DiscountAutomaticBxgyInput specifying title, startsAt, customerBuys (value type ALL_QUANTITY or specific quantity, and items as product/variant IDs), and customerGets (value as percentage or free, and items)
2. For customerBuys.items use a DiscountProducts input with productIds and productVariantIds; similarly for customerGets.items; both support collections via a DiscountCollections input
3. Set usesPerOrderLimit to cap how many times a single order can trigger the BXGY logic; omitting it allows unlimited stacking within one order
4. Confirm discountClass defaults to PRODUCT for BXGY; set combinesWith if you want this discount to stack with other discount classes
5. Query the returned automaticDiscount node including status, startsAt, endsAt, and customerGets to verify the mutation succeeded
6. Test by adding the qualifying buy items to a cart and querying cartLines with discountAllocations to confirm the get items receive their discount