A warehouse management system (WMS) is software that records and manages every movement in a warehouse, from receiving and put-away to order picking, packing and dispatch, by location, lot and quantity. Stock is tracked in real time through barcode or RFID scans, and data is exchanged with ERP, transport and customer systems.
How does a WMS differ from an ERP stock module?
An ERP holds the information that "there are 500 units of a product in the warehouse". A WMS knows in which aisle and rack slot, with which lot and expiry date those 500 units sit, and tells staff where to pick from.
| Topic | ERP stock module | WMS |
|---|---|---|
| Stock information | Warehouse and quantity | Location, lot, serial no., expiry date, pallet |
| Task management | None or limited | Put-away, picking and counting tasks |
| Data entry | In the office, document-based | On the floor with handheld terminals, barcode, RFID |
| Measurement | Financial value | Productivity, error rate, handling time |
What flow do the core modules follow?
- Receiving: The incoming vehicle is matched with an advance shipping notice (ASN), pallets are scanned, and shortages and damage are recorded.
- Put-away: The system suggests a location based on the product's size, turnover rate and rack capacity. Rack layouts are explained in the warehouse racking systems entry.
- Inventory management: Lot, serial number and expiry date are tracked; the issue rule is defined as FIFO, LIFO or FEFO.
- Order picking: Orders are grouped by wave, zone or batch picking logic; staff are directed along the shortest route.
- Packing and dispatch: Cartons and pallets are labelled, the vehicle loading sequence is set, and delivery note or e-delivery note (e-İrsaliye) data is generated.
- Counting: Cycle counting is carried out, periodically counting specific locations without shutting the warehouse. Methods are in the warehouse stock count entry.
Barcode or RFID?
In most warehouses barcodes are sufficient: they are cheap and every handheld terminal reads them. The 18-digit SSCC barcode is used at pallet level and the GTIN at product level. RFID tags allow bulk reading without line of sight; they are preferred for high-value products and where automatic recording is wanted when passing through a gate. The technologies are compared in the barcode, QR code and RFID entry.
Which systems does it talk to?
- ERP: Orders and product master data come in; stock movements and dispatch confirmations go back.
- TMS: The volume and weight of the cargo to be shipped are passed to the transport plan.
- Customers and suppliers: ASNs, stock reports and dispatch notices are shared via EDI or API.
- GİB (Revenue Administration): The dispatch document is created through e-İrsaliye integration.
Why is a WMS important in a bonded warehouse?
In a bonded warehouse (antrepo), goods not yet released for free circulation wait without duties being paid. The operator is obliged to keep stock records showing the entry, exit and handling of goods and to present them during customs inspections. A WMS keeps this record at declaration-number level: which pallet entered under which warehouse declaration, how much has been withdrawn and the remaining quantity are visible in real time. If bonded and free stock are in the same building, the system tracks the two separately. The legal side of the difference is explained in the warehouse vs bonded warehouse entry.
Common mistakes
- Switching to software before setting up a location system
- Loading incomplete master data (product dimensions, weight, units per carton)
- Continuing to work with paper lists instead of handheld terminals
- Not reconciling stock differences between ERP and WMS daily
Linking stock and dispatch data to the transport side is handled together in the warehousing and distribution and real-time tracking services.