Merging creates a new Shopify product with new variant IDs. Third-party fulfillment services that track products by Shopify ID need to be told about the new IDs. This page covers the providers we see most often, with the exact steps for each.
For general inventory behavior after a merge, see Managing inventory after product merging.
The rule that applies to every provider
Do not reimport the original products from your supplier after merging. A reimport recreates the old product IDs in your Shopify store, which competes with the merged product and causes duplicate listings, split inventory, and broken links.
Pause the supplier's automatic product sync before you merge if you are unsure. Re-enable it only after you have reassigned the merged product on the supplier's side.
Order routing
Order routing is the feature that makes merged products work with fulfillment services that identify products by Shopify variant ID. Enable it from Settings in the Merges app (the checkbox is labeled "Route orders to originals").
The problem it solves
When a merge is saved, the merged product has new variant IDs. A fulfillment service that was already syncing with your original products has no record of the new IDs. When a customer buys a merged variant, the fulfillment service receives a variant ID it does not recognize and the order fails to route.
Fulfillment services that track products by Shopify variant ID (Printful, Podbase, and similar) rely on those original IDs remaining reachable. Without Order routing, merged products break their fulfillment pipeline.
What it does
When a customer places an order for a merged variant, Order routing intercepts the order before the fulfillment service picks it up and swaps the merged variant ID for the original source variant ID. The fulfillment service sees an order for an ID it already recognizes and fulfills normally. The customer sees the merged product they bought.
Requirements
- The original source products must remain archived in your store, not deleted. Order routing reads their variant IDs at order time.
- Order routing must be enabled on an active subscription. Check Settings.
Which providers need it
| Provider | Requires Order routing |
|---|---|
| Printful | Yes |
| Podbase | Yes |
| Spark Shipping | No (SKU-based) |
| GigaB2B | No (SKU-based, but needs manual remap by their support) |
| Shopify Fulfillment Network | No |
Troubleshooting
If orders for merged products are not routing to the fulfillment service:
- Confirm Order routing is enabled in Settings.
- Confirm the original source products are archived and have not been deleted.
- Confirm your Merges subscription is active.
Printful
Printful identifies products by Shopify variant ID. After a merge, the new variant IDs will not match anything in Printful, and stock and fulfillment will break unless you connect the merged product back to the original Printful variants.
The supported workflow:
- Keep the original Printful-linked source products archived in your Shopify store.
- Enable Sync original products in Merges Settings. Turn on the toggles you need (at minimum, Inventory) for the Printful-associated location.
- Enable Order routing (Route orders to originals) in Merges Settings.
With both features enabled, inventory on the merged product mirrors the original Printful variant's stock, and orders placed on the merged product are rewritten to use the original variant IDs before they reach Printful.
Do not reimport products from Printful's catalog after merging. A reimport will recreate the source products and split your inventory.
Full setup guide: Printful setup.
Spark Shipping
Spark Shipping identifies products by SKU rather than Shopify variant ID. Because Merges preserves the original SKUs on merged variants, Spark Shipping recognizes the merged product automatically on its next sync cycle.
Steps.
- Save the merge.
- Confirm each merged variant carries the same SKU as the original source variant.
- Wait for Spark's next sync cycle. Stock will populate automatically.
No manual reassignment is needed. Order routing is not required for Spark Shipping.
If duplicate product records appear in Spark's dashboard after a merge, wait until you have confirmed the merged product is syncing correctly, then delete the originals in Spark.
GigaB2B
GigaB2B assigns products to its internal catalog by Shopify variant ID, not by SKU. When Merges creates a merged product with new variant IDs, GigaB2B's existing mappings no longer resolve, and stock drops to zero on the merged product.
Resyncing requires GigaB2B's side. Their SKU-based remap is not self-service; you need to contact their support.
Steps.
- Save the merge.
- Confirm each merged variant has the same SKU as the original GigaB2B source variant. Merges preserves SKUs unless you edited them in the editor.
- Email GigaB2B support with:
- Your store URL.
- The merged product's Shopify product ID.
- The list of merged variant SKUs that should map to their catalog.
- Ask them to remap the SKUs to the new variant IDs.
- After they confirm, enable Sync original products (Settings) so stock stays accurate on future updates.
Do not reimport from GigaB2B's catalog while waiting. A reimport will recreate the source products, split your inventory, and leave you with duplicate listings to clean up.
CJdropshipping, Spocket, Zendrop, and other dropshipping apps
Most dropshipping apps reference products by Shopify product ID. After a merge, the merged product will show zero stock on their side until it is reassigned. The steps:
- Check the app's documentation or support to confirm whether they reference products by ID or by SKU.
- If by ID, open a support ticket with the merged product ID and the source products' identifiers. Ask them to reassign.
- If by SKU, confirm the SKUs on the merged variants match the supplier's catalog. Stock will update on the next sync.
- Do not trigger a product reimport.
Shopify Fulfillment Network and 3PLs
If a 3PL (including Shopify Fulfillment Network) manages stock via Shopify's native fulfillment service API, the merged product is visible to them as soon as Shopify reflects it - typically seconds. The 3PL's system should pick up the new product on their next read.
If they track products by an internal SKU rather than Shopify ID, confirm the merged variants carry the same SKUs as the source variants. Merges preserves SKUs from the source products unless you edit them in the editor.
Custom or legacy fulfillment integrations
If your fulfillment integration is custom-built or uses an older API:
- Identify what the integration reads - Shopify product ID, variant ID, SKU, or an external identifier stored in a metafield.
- If product/variant ID: update the integration's mapping to the merged IDs.
- If SKU: verify SKUs match and wait for the next sync.
- If metafield-based: ensure the metafield is defined in Settings -> Metafields and metaobjects and was populated before the merge.
If the integration stores data outside Shopify, you may need to push a manual update to the integration's system via API or CSV. Most vendors accept a "remap these old IDs to these new IDs" request.
Microsoft Business Central (BC Shopify Connector)
BC's internal mapping table keys on the original Shopify variant IDs. Running "Sync Products" after a merge only updates the staging tables, not the Item Cards, so merged variants remain orphaned in BC. If you are on BC, contact support before merging; we can walk through the resync path.
Incompatible systems
Some systems cannot be made to work with merged products. Their sync models overwrite or reject Merges' output in ways we cannot work around.
BigBuy
BigBuy performs a destructive catalog sync, which overwrites all product data in your Shopify store from BigBuy's catalog on each sync cycle. After a merge, BigBuy recreates the original products and the merged product is orphaned. We do not recommend merging products managed by BigBuy.
Gooten
Gooten's API does not expose the endpoints we need to implement Order routing. Their mapping is variant-ID-based and they do not support manual SKU remap at scale. Merchants on Gooten should not merge products fulfilled by Gooten.
If you are on either platform and still want to consolidate your catalog, contact support first. We may be able to recommend an alternative approach for your specific setup.
When to split a merge instead
If a fulfillment provider cannot handle reassignment - or the cost of reassigning is high - consider whether the merge is worth it. A good sanity check:
- If reassignment takes longer than 30 minutes per product, batch your merges so the reassignment work is predictable.
- If the provider refuses to reassign, keep the products separate. Merges is only valuable when the downstream integrations can keep up.
Need help
Tell us the provider and what is happening. Email support@merges.io with:
- The merged product URL.
- The fulfillment service name and (if relevant) your account email with them.
- What you see in the merged product versus what you expected.
We have seen most of these cases and can usually point to the exact step the provider needs from you.