Using Shopify Shipping Rates With 3rd Party Software

Payments + Shipping & Fulfilment

Topic summary

Main issue: A high‑volume Shopify merchant using ShipWorks via Stamps.com wants to use Shopify’s lower USPS Priority Mail Cubic rates (reported 10–20% cheaper) within ShipWorks to save ~$500/month. Printing labels directly in Shopify is described as too cumbersome for the warehouse workflow.

Key details: Priority Mail Cubic is USPS pricing based on package volume, often cheaper for small, heavy parcels. The goal is to access Shopify-negotiated rates through a 3rd‑party shipping tool (ShipWorks) instead of Stamps.com.

Proposed paths:

  • Configure and use Shopify Shipping Services. A third‑party “Multi Carrier Shipping Label” Shopify app was suggested to print labels for major carriers (e.g., Stamps.com/USPS/UPS/FedEx) and potentially streamline high‑volume workflows.
  • Build a private app and use Shopify API credentials to integrate Shopify with the 3rd‑party software; feasibility not yet verified.

Outcome/status: No confirmed way was provided to plug Shopify’s discounted rates directly into ShipWorks. The thread remains unresolved, with the open question of whether API-based integration can legally/technically expose Shopify rates to external software.

Summarized with AI on January 3. AI used: gpt-5.
1

I’m currently on the Shopify advanced plan and ship about 50+ order per day using Shipworks by Stamps.com. My Shopify orders import directly into Shipworks, it works great and significantly reduces opportunities for errors in my operation.

The Priority Mail Cubic Rates in Shopify are 10-20% lower than those in my Stamps.com account that I have connected to Shipworks. Is there any way connect the Shopify shipping rates to my Shipworks software to replace my Stamps.com account? If so, the savings would be greater than $500/month.

Unfortunately, printing shipping labels through Shopify is very cumbersome when shipping a large volume of orders and it’s not a feasible shipping solution for my warehouse staff.

2

Hi @Sneiv ,

For using Shopify Shipping Rates you need to configure with Shopify Shipping Services.

And if you are looking for a shipping solution that allows you to print shipping labels effortlessly for top carriers like Stamps.com, USPS, UPS, FedEx, and so on, then Shopify Multi Carrier Shipping Label App is the ideal option.

3

Were you able to find a solution to this? The only solution I’ve come across is creating a private app and using the API credentials to integrate with the 3rd party software, though I’m not sure if it works yet.