How it works
When items are passed to the cartonization engine, Zonos checks each item for a packingConfiguration.stackConfiguration. If stacking is configured, the engine groups stackable items by their stackGroup and reduces the effective height of the stack using the stackDepth value—how far each item nests into the one below it. The stackLimit caps how many items can be stacked together in a single group.
The result is a more compact carton that reflects real-world packing, which leads to a lower dimensional weight and a more accurate shipping rate.
Stacking does not change existing behavior for items without a packingConfiguration—only items explicitly configured for stacking are affected.
Configure stacking
Stacking can be configured at the item level—saved directly on a Catalog item so it applies automatically every time that product is cartonized—or per request by passing the configuration inline when building an order via itemCreateWorkflow.
Add stacking configuration directly to a Catalog item so it is automatically applied every time that product is cartonized.
- Go to Dashboard -> Catalog.
- Click on the catalog item you want to configure.
- Scroll to the Stacking section on the item detail page.
- Enter the following fields:
- Stack depth — How far (in the item's dimensional unit) one item nests into the item below it.
- Stack group — A label that groups stackable items together. Items sharing the same stack group will be stacked with each other.
- Stack limit — The maximum number of items that can be stacked in a single group. Leave blank to stack all items in the group together.
- Click Save.
Stack configuration fields
| Field↕ | Type↕ | Required↕ | Description↕ |
|---|---|---|---|
stackDepth | Decimal | Yes | How far (in the item's dimensional unit) one item nests into the item below it. |
stackGroup | String | No | A grouping key for items that can stack together. Only items sharing the same stackGroup will be stacked with each other. |
stackLimit | Int | No | The maximum number of items that can be stacked in a single group. If omitted, all items in the group are stacked together. |
What happens if I don't set a stackGroup?
All items with a stackConfiguration but no stackGroup are treated independently. They won't be grouped with other items for stacking purposes.
Can I mix stackable and non-stackable items in the same order?
Yes. Only items with a packingConfiguration.stackConfiguration are stacked. All other items are cartonized normally.
What if my items exceed the stackLimit?
If the number of items in a stackGroup exceeds the stackLimit, Zonos creates additional stacks as needed. For example, 12 bowls with a stackLimit of 8 would produce one stack of 8 and one stack of 4.
Is stacking visible in the 3D cartonization display?
The 3D cartonization rendering of stacked items is being improved. Stacked items may appear visually offset in the current 3D display. Accurate stacking visualization is planned for a future release.
Stacking
Configure how nestable items stack together during cartonization for more accurate shipping rates.
Stacking lets Zonos know that certain products can nest or stack into each other—like bowls, cups, or trays—so the cartonization engine can calculate the true packed volume instead of treating each item as a separate, full-height unit. This produces more accurate and competitive shipping rates by reflecting how these items are actually packed.
For example, 8 ceramic bowls each measuring 4×5×4 inches would normally be calculated as 8 separate units stacked at full height. With stacking configured, Zonos accounts for the nesting depth of each bowl and packs them as a single compact stack, significantly reducing the calculated shipping volume.