The Master Inventory System in Synkro is designed to help merchants who sell made-to-order products stay in sync with a shared base inventory—typically a raw material or blank item.
This system ensures that any number of "derivative" products (such as printed variations) always reflect the same inventory level as a designated "master" product (the blank or base version). Whenever inventory changes happen—either through sales or manual updates—Synkro keeps everything synchronized automatically.
How It Works
1. Designate a Master Product
Choose the blank/base product that will act as your master and add the tag: synkro-inventory-master

2. Link Derivative Products
All derivative products (printed versions, made-to-order variants, etc.) must share the same SKU or the same barcode as the master. These products should not have the synkro-inventory-master
tag.
Inventory Syncing Logic
- When a derivative product is sold, Synkro reduces the inventory of the master product by the same quantity.
- Synkro then syncs the new inventory level from the master to all other linked derivatives.
Example
Let’s say you sell printed t-shirts that are made from a common blank:
Product Setup
Order Comes In:
- Dog Print x 3
- Cat Print x 2
Total: 5 units sold (from the same master SKU grey-md-tshirt
)
Inventory After Order:
This update happens automatically within seconds of the order being placed.
Manual Inventory Updates
If you need to adjust the inventory (e.g. after receiving new blank stock), always update the master product. Synkro will sync the new value across all derivatives instantly. This inventory change to the master product can also be applied through other means, such as a purchase order or 3rd party application.
When to Use This
The Master Inventory System is ideal for:
- Made-to-order products (e.g. custom prints)
- Shared raw materials
- Scenarios where you want inventory limits enforced across multiple variations of the same base item
How to enable Master Inventory System
- Start by installing Synkro in your Shopify store and creating a Synkro account. (See Same store inventory syncing step 1 & 2)
- Navigate into your Synkro settings to the "Master inventory location" tab, then click "Create a master inventory location in my store"

Setup complete 🚀
Now that the setup has completed, try adding the synkro-inventory-master
tag to your raw-material product. Next time you get an order for an item with the same SKU as a master product, that master product will be reduced and the resulting inventory will be propagated through all other derivative products which share the same SKU.
Use barcode for Master Inventory System
In some cases, using the SKU value to link master and derivative products may not be practical. Fortunately, Synkro’s Master Inventory System also supports Barcodes as an alternative identifier. To enable Barcode-based syncing, go to the Syncing Options section in your Synkro settings and select Barcode-based syncing.