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OMS and WMS

| Article: 3 min read | Business systems

OMS (order management system) accepts orders from all channels, tracks their statuses and decides where and how to fulfil them. WMS (warehouse management system) records goods coming in and going out, knows where everything is, and assigns work in the warehouse (Wikipedia, WMS).

In plain words

OMS answers the question "which order is this, what state is it in and what should be done with it". WMS answers "where is the product and who will pick it". The first sits above the order, the second above the shelf.

According to Wikipedia, the main function of a WMS is to record the receipt and removal of stock; the software can also track the exact location of goods, optimize use of space and coordinate tasks in the warehouse. At higher levels of complexity it plans work around customer orders and transport (Wikipedia).

The description of OMS in this article is a general explanation with no source: order intake, stock records, choosing a warehouse or fulfilment channel, returns.

Why a store needs it

  • OMS: orders come from the site, Rozetka, Prom, Instagram, the phone. Without a single place, they are easy to miss or to sell the same item twice.
  • WMS: when the warehouse is big or several people work in it, you need bin addresses, scanning and a picking order, otherwise you get picking errors and "lost" stock.

When you need it

OMS:

  • several sales channels (marketplaces, omnichannel);
  • several warehouses or pickup points;
  • orders are often changed, split, cancelled.

WMS:

  • many SKUs and storage locations;
  • several people pick orders at the same time;
  • you need stock accuracy down to the unit, batch or series.

When it's still too early

According to Wikipedia, small warehouses can manage with spreadsheets or paper records, and a service business with a simple stockroom can manage with an inventory program. The same goes for a store: a small warehouse, one channel, a few dozen orders a day — the store platform and stock records in the accounting system are enough.

How it connects with other systems

  • With the store platform: orders and stock are exchanged through API and integrations.
  • With ERP: according to Wikipedia, ERP inventory focuses on financially significant figures and usually lacks the depth of a specialized WMS. A WMS can be standalone or an ERP module.
  • With fulfilment: if an operator runs the warehouse, its system (the equivalent of a WMS) returns statuses and stock to you. Nova Poshta, for example, offers integrations of its fulfilment with CRM systems and platforms (Nova Poshta).
  • With delivery: the OMS or platform creates waybills for the delivery service, see last mile.
  • With CRM: the CRM sees the order status, while the OMS manages it.
  • With PRRO and accounting: the receipt and sales document are produced from the order, see accounting system.

Common mistakes

  • Buying a WMS without order in the warehouse: the system reproduces the mess faster.
  • Stock on the site and in the warehouse live separately.
  • Not accounting for returns and uncollected orders (returns, cash on delivery).
  • Installing a complex system when the platform's module is enough.

FAQ

What are OMS and WMS in simple terms? OMS manages orders, WMS manages the warehouse and where goods are located.

How does OMS differ from WMS? OMS works with the order: what to send, to whom, from where. WMS works with goods in the warehouse: where they are and how to pick them.

Does a small store need a WMS? Usually not, while the warehouse is small and all stock is visible in the accounting records.

Do ERP systems include OMS and WMS? They often have order and warehouse modules, but these are less deep than specialized systems.

Sources

There is no fresh (2025–2026) data on OMS and WMS in Ukrainian stores.

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