ShipStation Package Recommendations vs automatic box selection

What ShipStation's feature does

ShipStation calls the feature Packing Recommendations. The button on the order says Package Recommendations. This is how ShipStation describes it, as of October 30, 2026.

What it recommends

"Packing Recommendations automatically recommends the best package configuration for an order based on your product dimensions, weights, and available packages." The plan uses "the fewest packages needed for the order."

How you use it

"Open an order, select Package Recommendations, review the plan, and apply it in one click to create the multi-package setup." You can ignore the plan and set packages by hand. It also follows packaging rules such as an item set to ship alone.

What it needs

Dimensions and weights on your products, and custom packages with dimensions and a maximum weight. The help center lists it as a beta in ShipStation Labs. ShipStation's blog, updated October 27, 2026, says it is "now available to everyone."

What its documentation does not say

ShipStation's documentation describes Packing Recommendations as a step on one open order. As of October 30, 2026, it does not say:

• That it runs when an order imports.
• That an automation rule can run it. ShipStation's list of rule actions, updated October 19, 2026, has Set Package Dimensions and Set Carrier/Service/Package. It has no action for Packing Recommendations.
• That it runs on a batch of orders. The documented bulk option applies a saved Package Set, a fixed group of packages that ShipStation says does "not assign order items."
• How it chooses between two boxes that both hold the order. The stated goal is the fewest packages.

ShipStation changes fast. If your account offers more than its documentation describes, go by your account.

What ShipExtension does

• It sets the box without anyone opening the order. Rules can run as each order imports. Scheduled or manual runs cover every order awaiting shipment, including orders edited after import.
• Calculate Package is a rule action. Your rule's conditions decide which orders it touches, and they can combine SKUs on multi-item orders.
• It picks from your own box list. The smallest box that fits wins, which is also the one with the lowest dimensional weight. Mark a box out of stock and it is skipped. Limit a box to the warehouses that stock it.
• Every unit has to fit the box in three dimensions, turned any way, and the box has to hold their combined volume. It is a fit check, not a full packing simulation. When ShipStation lists a kit with its component items, the components are what get fitted.
• It tries one box for the whole order first, and splits into packages only when no box holds it. Writing a multi-package shipment needs a ShipStation V2 API key.
• It writes the box size and weight to the order. If the box is linked to one of your ShipStation custom packages and a V2 API key is connected, it sets that package instead.

How box optimization works.

When ShipStation's built-in is enough

• Your packers open every order anyway. One click on an order that is already open costs little.
• Most orders are one item. ShipStation's product defaults can set package dimensions on single-item, single-quantity orders.
• The same item mixes repeat. ShipStation's SmartFill runs at import: "auto-fill checks your two most recent shipments with the exact same mix of items. If both used the same weight and dimensions, it fills them in." For a new mix, it fills nothing until that mix has shipped twice the same way.
• You want the fewest boxes, and your volume is low enough to review each plan.

Either way, you do not have to leave ShipStation. ShipExtension works through the ShipStation API, so your stores, carriers, rules, and labels stay where they are. Keep Packing Recommendations for the orders you open by hand, and let ShipExtension set the box on the rest.