How It Works
ShipExtension connects to your existing ShipStation account over the API. It reads your orders and products, runs your rules, and writes results back to the order — it never changes your ShipStation configuration, carriers, or stores. Here's exactly where it sits in your workflow.
Execution Order
ShipStation's native automation and ShipExtension never race each other. They run at different points in the order's life.
ShipStation's native automation rules fire once, at import, exactly as they do today. Nothing about that changes.
Orders process live as they come in, on a schedule you set, or in one-click manual runs — always on the order ShipStation's rules already shaped.
Writes change only the fields your ShipExtension rules target — box, weight, carrier, service, tags. Everything else on the order is preserved, and writes that wouldn't change anything are skipped.
Rate Shopping
Rate shopping runs against the carrier accounts already connected to your ShipStation — we don't broker rates or insert our own accounts. Every quote is the price you actually pay, negotiated discounts included.
For each order, all of your eligible accounts and services are compared in a single rate request. The winning carrier, service, and billing account are written back to the order, so the label purchases against the right account every time. You control which carriers and services are eligible, per rule.
Box Optimization
Box optimization runs on your ShipStation product records. We sync each SKU's dimensions and weight, and you can override any value per product inside ShipExtension — overrides are never touched by a re-sync, so a measured value you enter once stays put.
Done-for-you setup includes cleaning up your dimension data before any rule goes live, because box selection is only as good as the measurements behind it.
Missing-dimension handling is configurable. By default we don't guess: an item without full dimensions is left out of the calculation, and if nothing on the order is measurable the box step skips that order and leaves it for your normal process. If you'd rather keep those orders moving, you can enable an educated-guess fallback instead.
Packing Slips
Pick a ShipStation batch (or select orders directly), choose a template, and ShipExtension generates one combined PDF in the background — no per-order clicking. Templates are retailer-compliant for Home Depot, Macy's, and Lowe's vendor programs, or your own design.
Output is configurable: slips only, or slips interleaved with your ShipStation shipping labels — label, slip, label, slip — so each order's paperwork comes off the printer together and pack stations never collate by hand.
When the batch is ready, download the single PDF and print it in one job, or use the PrintNode integration to send output directly from ShipExtension to whichever printer you run.
Volume
The primary mode is live: orders process one at a time as they arrive, so volume spreads out and there's normally no big batch to wait on. Scheduled background runs and manual runs are there when you want a bulk pass over everything awaiting shipment.
Every ShipStation API call goes through a client that reads ShipStation's rate-limit headers and paces itself. When a limit is hit, the run waits out the window and retries — orders are never dropped because the API said slow down. Field writes are batched 50 orders per API call, and any write that wouldn't change the order is skipped entirely.
In practice: bulk field updates across 500 orders finish in minutes, and a full rate-shopped 500-order run typically completes in 20–40 minutes, with live per-order progress in the dashboard the whole way.
Connect your ShipStation account and run your first rules in dry-run mode — nothing writes until you say so. Free 14-day trial, no credit card required.