Fulfillment Constraints API reference
The Fulfillment Constraints API enables you to have a higher degree of customization when defining fulfillment and delivery strategies. The API includes two key objects: Input and FunctionResult.
The Input object is the complete schema that your function can receive as input.
The input includes the following objects:
Cart: The context of the current purchase proposal.Locations: The locations that stock the items. This object includes metafields.FulfillmentConstraintRule: A reference to the function owner, the Fulfillment Constraint Rule object. This object includes metafields.
The following example shows an input query:
The following example shows the resulting input to the query:
FunctionResult
Anchor link to section titled "FunctionResult"The FunctionResult object is the shape of the function's output.
Output objects can return a value of 0 to n fulfillment constraints. The following function result specifies that deliverable cart lines 1 and 2 must ship or fulfill from same location, and lines 3 and 4 must ship or fulfill from location 1:
Constraints reducer
Anchor link to section titled "Constraints reducer"In scenarios where FunctionResult returns constraints that can be further combined, a reducer logic runs to combine constraints before data is passed to Shopify.
In this scenario, the output contains two constraints with the same type MustFulfillFrom and the same location ID 1. These two constraints can be combined because DeliverableCartLine 1, 2, 3 and 4 should all fulfill from location 1.
In this scenario, the output contains two constraints with the same type MustFulfillFromSameLocation. Shopify combines them because DeliverableCartLine 2 must be fulfilled from the same location as DeliverableCartLine 1, 3 and 4.
In this scenario, the output contains two constraints with different types. DeliverableCartLine 2, 3 and 4 must fulfill together and at the same time. DeliverableCartLine 2 must fulfill from location 2. To meet both constraints, DeliverableCartLine 3 and 4 must fulfill from location 1.
Constraints conflict
Anchor link to section titled "Constraints conflict"In scenarios where FunctionResult returns constraints that are mutually exclusive, checkout won't return any shipping rates.
In the following example, DeliverableCartLine 1 and DeliverableCartLine 2 can't be fulfilled together because they must fulfill from Location 1 and 2 respectively.