Shopify Dynamic Shipping with Google Merchant Center

✅ The Situation
We want to sell all of our current Shopify products on Google Shopping and Google Ads, with the ability to continuously grow and expand the catalogue over time.
Shipping in Shopify is merchant calculated (dynamic) using ShipZip. Shipping varies by:
• Weight
• Postcode / zone
• Product type
Shipping is calculated accurately at checkout based on these rules.

✅ The Problem
Google Merchant Center does not directly support complex dynamic merchant calculated shipping logic from Shopify.
The default shipping setup options inside GMC are:
• Flat rate shipping
• Price based shipping (based on order value)
• Weight based shipping tables
• Destination based shipping (country/state/postcode ranges)
• Carrier calculated shipping (limited availability by country)
• Shipping labels (filter based rules)
• Free shipping thresholds
• Handling time and transit time settings
All of these options require manual rule creation inside GMC.
For our store, this is not practical because:
• We plan to significantly increase the number of SKUs over time
• Product weights vary significantly
• Shipping varies by postcode
• Inventory constantly changes
Recreating our shipping logic inside GMC using weight tables or postcode rules would require thousands of calculations and ongoing manual maintenance.

✅ What We Need
We need Google Shopping to display shipping costs that are calculated at Shopify checkout as close as possible to the actual checkout rate, without manually rebuilding shipping rules inside GMC.
We also do not want to constantly adjust shipping settings in GMC every time products are added or removed from the catalogue.
The solution must be:
• As accurate as possible
• Scalable as the catalogue grows
• Policy compliant
• Low maintenance
• Automatically adaptable when products change

✅ Possible Scalable Solutions (Ranked by Preference)
1️⃣ Use Shopify / ShipZip Live Shipping via a Feed App (Most Preferred)
Use a feed app (such as Simprosys, AdNabu, or CedCommerce) that pulls Shopify’s live checkout shipping rates — including ShipZip logic — and sends them to Google via the Content API. This allows Google to use merchant calculated shipping directly from Shopify instead of recreating shipping tables inside GMC. It is the most scalable and accurate solution and automatically adjusts as products are added or removed.

2️⃣ Use Google Content API with Item Specific Shipping
Send product data to Google using the Content API and attach shipping costs at the SKU level. Advanced feed apps can calculate shipping per product based on Shopify rules and pass that value to Google automatically. This provides strong accuracy but may require a more advanced or premium feed configuration.

3️⃣ Use Shipping Labels to Group Products (Least Preferred – Less Accurate)
Assign shipping labels (e.g., Zone1, Bulky, Standard) within Shopify or the feed app, then create shipping rules in GMC based on those labels. This reduces the number of shipping rules by grouping similar products, but it relies on averaged or simplified shipping logic. It is less precise and may not always match checkout shipping exactly, making it the least preferred option.

✅ Open to Additional Solutions
If there are other technically viable methods to achieve this objective — particularly solutions that improve accuracy, scalability, or automation — we are open to considering them.

✅ Objective
The goal is to mirror Shopify’s dynamic merchant calculated shipping in Google as closely as possible, without relying on manual weight based tables or constant updates inside Google Merchant Center.