Four systems touch an order, and their names give little idea of where one stops and the next starts. Following one order through them makes the boundaries clear.
01The journey of one order
- The customer orders, on the website, through a salesperson or in a shop. The order management system records it, checks payment and reserves stock.
- The OMS decides where to fulfil it from: which warehouse or store has the goods and can deliver soonest at least cost.
- The warehouse management system at that site creates a pick task, directs a person to the right bin, confirms each item by scan and packs the parcel.
- The carrier collects it. Tracking flows back through the OMS to the customer.
- The ERP records the sale, reduces stock value and raises the invoice. Finance sees revenue and the cost of goods.
- Supply chain software notes that stock of that item is lower, compares it with forecast demand and proposes a purchase order to the supplier.
02What each system is really for
- OMS: the promise to the customer, across every channel.
- WMS: the physical work inside the four walls.
- SCM: the plan for what to buy, make and move next.
- ERP: the official record of stock and money.
03Where it goes wrong
Problems appear at the joins. The website sells stock the warehouse has already picked for another order. The warehouse ships and the ERP is updated a day later. Purchasing reorders from a stock figure that was never right. Each is a failure of the systems to share one view of stock in time.
04Do you need all four?
A business with one sales channel and one small store room can run on an ERP's own order and inventory functions. An OMS earns its place with multiple channels, a WMS with a busy warehouse, and SCM software with long lead times or many suppliers.
In short
- OMS owns the customer's order; WMS owns the work in the warehouse.
- SCM plans ahead; the ERP keeps the official record.
- Most failures happen where the systems meet, usually over stock.
- Add each system when the complexity it handles has actually arrived.
Questions
What causes overselling?
Channels selling against separate or stale stock figures. The fix is one pool of available stock that every channel reads and every order reduces immediately.
Can an ERP replace a WMS?
For a simple store room, yes. An ERP knows quantities by site. A WMS knows the bin, directs the picker and confirms by scan, which a busy warehouse needs.
Where does point of sale fit?
A till is another source of orders and another place stock leaves from. In a multi-channel business it feeds the same order and stock systems as the website.
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