Add Item to Cart
Add a product to an existing cart
POST
Documentation Index
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This endpoint adds one or more items to a cart. If the item already exists, it updates the quantity. Inventory availability is checked in real-time.
Authentication
This endpoint requires a valid API key withcarts:write permissions.
Path Parameters
The unique identifier of the cart
Request Body
Product ID to add
Product variant ID (required if product has variants)
Quantity to add (must be positive)
Custom price in cents (requires special permissions)
Special instructions for this item
Custom fields for the item
Check inventory availability before adding
Replace existing quantity instead of adding to it