How to synchronize inventory across ecommerce platforms.

Keeping inventory levels accurate across multichannel platforms can be challenging.
Posted Jan 17 2022
Inventory Management
Order Management System
Enterprise Resource Planning (System)
Transactional inventory
Keeping tracking inventory stock changes with receiving and deduction transactions.
Photo by Petrebels on Unsplash

Common challenges with syncing inventory availability with multichannel ecommerce

Whether you’re syncing inventory to one ecommerce platform or many, you’re going to encounter challenges. Commonly, getting the timing right is an issue.


Most ecommerce platforms let you update your inventory quantities through an API, so you’ll need to decide on a strategy to use those APIs. Do you setup a periodic background process to update your sales channels, or do you opt for a more real-time approach? There is no correct answer; it all depends on what makes the most sense for each platform. Though, the more channels you support, you may want to consider pushing syncs quicker to each channel.

Timing can be tricky during periods of high volume sales, as there is often lag between your warehouse/ERP and your orders. For example, if hundreds of orders are being placed each hour, but the orders are only consumed by your warehouse/ERP every 15 minutes, your ERP cannot know what the real inventory quantity-available is, since orders are allocating inventory in real-time on each ecommerce channel. In high-volume scenarios like this, it is worth considering scheduling your inventory syncs to occur only at low-volume times, like the middle of the night. On periods like Black Friday or Cyber Monday, consider turning off your inventory syncs altogether, since the order-export lag can easily lead to overselling.


The more platforms you’re on, the more likely that you’ll oversell. This becomes especially true when you have low levels of inventory for certain SKUs. For example, if you have 1 item left in stock, and you have it listed on your ecommerce site, Amazon, and Walmart, to the world at large, there are 3 available to purchase. If all 3 listings sell in between your inventory sync schedule, you’ve just created 2 unhappy customers.

Sources of truth

When considering your strategies for inventory syncs, you need to consider your sources of truth. Ecommerce software stacks often involve lots of players, and you need to determine which inventory system is the most accurate.

Your WMS or ERP may have the best handle on what is physically available in the building, but they may not be up to date on the latest order velocity, if they only receive orders once or twice a day. Even hourly order exports to the warehouse can create significant lag problems.

Your ecommerce site accounts for order velocity the best, but it doesn’t reflect for sales on other platforms.

If you have an OMS, you can craft the best strategy, because your OMS can receive syncs from the warehouse, and account for orders placed on all sales channels.


Sources of truth

One of the pitfalls of inventory syncs is that you’re pushing and pulling raw numbers of available units. Raw numbers (e.g. there are 5 in stock of a particular unit) are a blunt instrument for controlling inventory; they can work, but they lack important nuance. If there are 5 in in stock in the warehouse, but 4 were ordered before the warehouse could receive those orders, that “5” number is wholly inaccurate.

A solution is a transactional inventory strategy. Transactional inventory strategies allow for you to push context-based changes to inventory quantities. If the warehouse received a new shipment from the supplier and performed a transaction to add 100 units to the available stock, that transaction can be disseminated to an OMS, and further disseminated to your sales channels. In this example, the order velocity on each sales channel is irrelevant, because you are only informing each channel of new stock. In the same way, if the warehouse deducts inventory en masse for a wholesale account, and that transaction is coded properly, that transaction can be disseminated down to the sales channels.

To support a transactional strategy, your software must track inventory changes in coded transactions.

Syncing deltas

Not all ecommerce platforms support transactional inventory strategies. To account for this, and make the syncs as timely as possible, another strategy is to push “deltas” (or changes) to each channel. If you are supporting Shopify, Amazon, and Walmart, and an order is placed on Shopify, the Shopify inventory is correct, and the Amazon and Walmart inventory are now overstated. With a delta strategy, you push the new inventory quantity to all 3 channels. The Shopify inventory is updated (likely to the exact same number since that is where the order was placed), and the Amazon and Walmart quantities are updated reflecting the new and lower quantity. Since you are only syncing deltas, your inventory sync process is likely very fast, since it is only syncing the SKUs where the quantities changed, which is likely to be a small number of SKUs.

To support a delta strategy, your software must record the last quantity that was sent to each channel. With this data available, it is easy to quickly detect changes for each channel and push the delta quantities.

Inventory buckets

If your software supports it, you can create inventory buckets to dedicate stock to certain platforms. You could create a bucket for your ecommerce store, another for Amazon, and yet one more for Walmart. When new stock is received, you can transfer inventory from your main bucket to the buckets you’ve dedicated to the sales channels. In this manner, orders from one source cannot take stock from another, and you can eliminate overselling due to competing sales channels.

Inventory syncing with Orderwave

The good news is that Orderwave has enough features to support the strategies outlined in this article. We support unlimited warehouses, unlimited subsets (buckets), transactional inventory, and delta tracking. If you’re selling on multiple channels, or are simply running into inventory syncing issues due to timing, contact us today to get your inventory processes on track.

Get a handle on your inventory syncs today.