Reference
The operations
reference
The questions to settle before a platform decision: which system holds stock truth, which one owns the order promise, where the ledger takes its numbers from, and how it all connects.
Vendor-neutral throughout: no vendor can write the page that compares their competitors.
What each system owns
The market sells these as one product. Knowing which question you're asking changes what belongs on the shortlist.
Order management systems
What the order layer decides — which unit, from which location, to which customer, in what priority — and the four things that break when nothing owns that decision.
Stock control software
Stock is four numbers: on hand, committed, available and incoming. Which system is allowed to be right when two of them disagree, and what to ask any candidate.
Shopify inventory management
What the platform already does with stock across locations, where it stops, and the four reasons to add anything alongside it.
eBay inventory management
The same units offered on eBay and Shopify at once, the three setups that keep the counts level, and the one number eBay should be sent.
Amazon inventory management
Stock in Amazon’s fulfilment centres, on your own shelves, or both, and which count each channel sells from.
Warehouse management systems
What a WMS does from goods in to despatch, what Shopify covers on its own, the four kinds of WMS, and six questions for any vendor.
Stock as an operation
Before it's a software decision, it's a warehouse floor, a supplier and a number that has to be right.
Stock and fulfilment
Why stock desynchronises, what overselling costs, and how to work out whether a WMS or a 3PL is cheaper.
Inventory planning
The reorder-point arithmetic is one line. The inputs are estimates that each lie in a characteristic direction, and that is where the money is won or lost.
Consigned stock
Stock in one party’s building and another party’s ownership. Which direction it runs, the four moments title can pass at, and why one stock number cannot hold it.
What is a 3PL
Third-party logistics: what the warehouse does, how it compares with your own or FBA, and who owns the stock count once the stock is in their building.
Inventory turnover ratio
Cost of sales over average stock, days of stock, a worked example, and why the ratio is only as good as the ledger behind it.
CN22 and CN23 customs forms
From 1 June 2026 Royal Mail and Parcelforce postal shipments use a CN23. What it asks for, and why that data belongs on the product record.
The ledger, and the wiring
Where the money lands after all of the above, and how any of it is physically joined to Shopify Plus.
Accounting and stock
Where the ledger sits when a storefront, a stock system and an accounting package all have to agree, and the four reconciliations that break first.
Shopify and Xero
Four things have to cross and only one is the sale. The summary-versus-invoice decision shapes the ledger permanently, and it is usually made by a default.
Xero inventory management
Up to 4,000 finished items at average cost, by Xero’s own figures, and the three ways to run stock alongside it.
Sage stock control
What Sage 50 Accounts keeps in the Professional variant, and the three ways to run stock alongside it.
QuickBooks inventory management
Stock on the Plus and Advanced plans, a costing method fixed once chosen, and the three ways to run stock alongside it.
Systems that work with Shopify Plus
The four ways an ERP, WMS or stock system connects to Plus, and where each connection type breaks.
Applying it to your operation
Each page above sets out how the decision works. Choosing the product comes next, and it turns on specifics: which product holds committed stock per location, which connector survives a channel going down mid-sync, and what each arrangement costs to run rather than to licence.
We work those out against your operation, not against a datasheet.
The systems review applies all of this to your operation: which system is nominated to be right today, where the order promise is made, and which reconciliations someone is already doing by hand.
Start the systems reviewTell us what you need
What the systems are doing now, and what you need them to do. We'll tell you whether it's a platform problem or something cheaper.