ShipWave Channels

Preventing overselling

How ShipWave prevents overselling across multiple marketplace channels.

What is overselling?

Overselling happens when you sell more units than you have in stock. This forces you to cancel orders, which:
  • Damages your marketplace seller metrics
  • Can result in account suspension (especially on Amazon)
  • Creates a poor customer experience
  • May incur cancellation fees
ShipWave uses multiple mechanisms to prevent overselling.

Cross-channel inventory deduction

When an order comes in from ANY channel, ShipWave immediately reduces inventory on ALL OTHER channels:
  1. Order arrives from Amazon for 5 units
  2. ShipWave finds all other channels with this product (eBay, Walmart, etc.)
  3. ShipWave pushes updated inventory to each channel
  4. All channels now show reduced stock
This happens BEFORE the Shopify webhook fires, providing an extra layer of protection.

Real-time sync

Webhook-driven sync updates marketplaces within seconds of Shopify changes. This minimizes the window where inventory could be out of sync.

Safety buffers

Inventory buffers hold back stock, providing a margin of error during high-velocity sales or sync delays. Even if two orders come in simultaneously on different channels, the buffer provides breathing room.

Inventory floors

Floors prevent selling the very last units on marketplaces with strict cancellation penalties. Reserve a few units as safety stock.

Periodic reconciliation

The 15-minute cron job catches any discrepancies that slip through real-time sync. If inventory drifted out of sync, reconciliation fixes it.

Shopify as single source of truth

By using Shopify as the authoritative inventory source, there's no risk of counts diverging between systems. All channels read from the same source.

What to do if you oversell

If overselling happens despite these protections:
  1. Cancel the order on the marketplace (follow their cancellation process)
  2. Contact the customer to apologize
  3. Investigate the cause (check sync logs for failures)
  4. Increase your buffer to prevent recurrence
Occasional overselling can happen during extreme flash sales or platform outages. A good buffer minimizes this risk.

FAQs

Can overselling still happen?
In rare cases, yes. If two orders happen simultaneously on different channels before sync completes, overselling is possible. Buffers reduce this risk significantly.
How big should my buffer be?
It depends on your sales velocity. For slow-moving items, 2-3 units is enough. For fast sellers during promotions, consider 10-20% of inventory.
Does cross-channel deduction work in real-time?
Yes. When ShipWave imports a marketplace order, it immediately pushes updated inventory to all other channels.
What if a marketplace API is down?
The sync will fail and retry later. During outages, your buffer provides protection. Consider pausing channels during extended outages.

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