Path A

Path A is Snapcaster-managed fulfillment. Your Platform owns physical On-hand, while the Seller fulfils each Order from the Snapcaster dashboard. Your Platform never receives buyer PII.

Receive inventory.adjusted

Snapcaster sends the signed inventory.adjusted event when a sale commits units or a Cancellation or Refund releases units. The event carries seller_id and lines with sku_id, external_ref, and a signed delta. Apply the event as on_hand[sku] += delta.

A negative delta commits a sale. A positive delta releases a Cancellation or restocked Refund.

Return 2xx only after the Inventory adjustment is durably written or durably enqueued. Snapcaster releases the corresponding Committed hold after that acknowledgement. A premature acknowledgement can make a sold card browsable again.

Reconcile safely

Send asOf with a Listing push when the pushed On-hand snapshot was true earlier than receipt time. Snapcaster uses it to determine which Committed units that snapshot can release.

Read available from GET /listings when recovering from an outage or when your handler cannot deduplicate deltas. available is Snapcaster’s current buyer-purchasable quantity after Committed units are subtracted.

Deduct from exactly one source

For an inventory Subscription, inventory.adjusted is the Inventory adjustment. For a both Subscription, treat order.created as a pick, pack, and ship work order and still use inventory.adjusted as the Inventory adjustment. Do not also deduct during fulfillment.

Use the Inventory adjusted webhook reference for the canonical Delivery payload.

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