Creates a checkout estimate with three operational modes:
Mode 1 - Direct Items: Provide items directly (original behavior)
items arrayMode 2 - Cart-Based: Pull items from saved cart
useCart: trueMode 3 - Cart with Overrides: Pull from cart with modifications
useCart: true and itemOverridesCart behavior (modes 2 & 3):
validItems[] are eligible to be checked out.invalidItems[] are ineligible right now (e.g., no eligible offers). They stay in the cart unless you remove them.invalidItems[] intentionally contains the minimal identifiers + reason; match it back to your cart display by productId (+ retailer when relevant).Customer identification is required: customer_id OR (wallet_address + wallet_network).
Legacy alias for commerce-scoped API keys. Prefer x-api-key with scope=commerce.
Step 1 request. Supports direct items (Mode 1) or cart-based estimation (Modes 2–3). When useCart: true, Pepay reads the saved cart but does not mutate it.
"cust_123456"
When true, items are loaded from the saved cart for the provided customer identifier.
Mode 1 only (direct items). Forbidden when useCart: true.
Mode 3 only. Requires useCart: true. Use quantity: 0 to exclude items for this estimate without mutating the cart.
Reserved for future shipping estimates; currently ignored.
Reserved for future shipping estimates; currently ignored.