Reverses a previous fulfillment, returning items to allocated status.

When to Unfulfill

Use this endpoint when:

• Items were fulfilled in error
• Stock is discovered to be unavailable after fulfillment
• The fulfillment needs to be reassigned to another location
• A shipment was cancelled before pickup

Request Requirements

You must provide:

• fulfillment_ids: Array of fulfillment IDs to reverse (required)
• The fulfillment IDs must exist in the fulfillment order's fulfilled line items

Effects

When you unfulfill:

1. Associated shipments are cancelled (if not already cancelled)
2. Line items return to allocated status
3. Fulfillment ID, shipment IDs, and partner reference are cleared from items
4. Items with the same ID and status are merged
5. Order status is recalculated
6. Webhooks are triggered

Inventory Impact

If inventory management is enabled:

• on_hand is increased by the unfulfilled quantity (restoring stock)