Master Inventory System

Sync inventory across multiple made-to-order products using a shared master SKU or barcode

Last updated
May 20, 2025

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

Add the tag "synkro-inventory-master" to the product which will serve as your master inventory product

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

  1. When a derivative product is sold, Synkro reduces the inventory of the master product by the same quantity.
  2. 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

Title SKU Tags Inventory
Blank Grey T-Shirt grey-md-tshirt synkro-inventory-master 3000
Cat Print On Grey T-Shirt grey-md-tshirt 3000
Dog Print On Grey T-Shirt grey-md-tshirt 3000
Bird Print On Grey T-Shirt grey-md-tshirt 3000

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:

Title Inventory
Grey Medium Blank T-Shirt 2995
Cat Print On Grey T-Shirt 2995
Dog Print On Grey T-Shirt 2995
Bird Print On Grey T-Shirt 2995

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

  1. Start by installing Synkro in your Shopify store and creating a Synkro account. (See Same store inventory syncing step 1 & 2)
  2. Navigate into your Synkro settings to the "Master inventory location" tab, then click "Create a master inventory location in my store"
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.

Close Modal