Pick the right box for every order - via one API call.
Send items and cartons, get back the cheapest viable box mix with exact 3D placements. In our reproducible benchmark that meant 44% fewer parcels and ~$11.31 saved per order at published Ground list rates.
Built for developers first.
- →REST + JSON with a full OpenAPI 3 spec and Swagger explorer
- →Unit-agnostic dimensions - inches, cm, whatever your WMS speaks
- →Say what to optimize: fewest-parcels, lowest-cost, or lowest-billable-weight
- →Batch up to 500 orders async with job polling, or 50 sync
- →Idempotency-Key support for safe retries
curl -X POST https://cartonpilot.com/api/v1/shipping-optimize \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"boxes": [
{ "id": "S", "dimensions": { "length": 10, "width": 8, "height": 6 }, "cost": 0.61 },
{ "id": "M", "dimensions": { "length": 15, "width": 12, "height": 10 }, "cost": 0.94 }
],
"items": [
{ "id": "MUG-01", "weight": 1.2, "quantity": 4,
"dimensions": { "length": 5, "width": 4, "height": 4 } }
],
"options": { "objective": "lowest-cost", "dimDivisor": 139 }
}'How cartonization works
1. Send order lines + your cartons
Item dimensions, weights, quantities, and your available box sizes (or a saved box set / SKU catalog key).
2. The solver packs in 3D
8 bin-packing algorithms test rotations and box combinations, honoring weight capacity, fragility, and stacking rules - in under a millisecond.
3. Get the cheapest viable plan
Box choice per shipment, exact item placements, fill rates, and billable weight - ready for your packing bench or rate shopper.
See your savings before you write code.
Paste an order (or a CSV) and the production engine shows parcels saved, box spend, and estimated FedEx/UPS Ground cost - right here.
Your order
| Item | L | W | H | lb | Qty | |
|---|---|---|---|---|---|---|
Audited against a standard 7-box corrugated line-up using a first-fit baseline vs. cartonpilot-ultra.
Add your items and run the audit to see how many parcels and how much box spend CartonPilot can cut.
Cartonization API FAQ
What is a cartonization API?
A cartonization API decides which box (or boxes) each order should ship in. You send item and carton dimensions; it runs 3D bin packing and returns the cheapest viable carton mix with exact item placements - so your WMS, OMS, or storefront can pick the right box before a packer touches the order.
How much can cartonization save?
In our published, reproducible benchmark, optimized cartonization shipped 44% fewer parcels and cut carrier spend by 37% at published FedEx/UPS Ground list rates versus a standard first-fit packer - about $11.31 per order. Run the free audit on this page to see your own numbers.
Does it handle dimensional (DIM) weight?
Yes. Pass your carrier's DIM divisor and every shipment returns actual, dimensional, and billable weight. There is a dedicated lowest-billable-weight objective that picks cartons to minimize what carriers actually bill.
How fast is the API?
The solver computes a pack plan in under 1 ms (median) per order. Measured server-side, API responses run about 20 ms p50 / 60 ms p95, excluding client network time.
Do I need to sign up to try it?
No. The free packing audit on this page runs the production engine on your own order data with no signup. The Free plan (1,000 items/month, no credit card) covers full API integration testing.
1,000 items/month free - no credit card. Or compare plans.