Order management systems: what an OMS does and when a growing business needs one
Once orders arrive from a website, marketplaces, stores and sales reps at the same time, spreadsheets and the e-commerce platform's back office stop keeping up. That's the job an OMS takes on.
US e-commerce sales reached $340.2 billion in the second quarter of 2026, seasonally adjusted, according to the Census Bureau. That was 17.1% of all retail sales and 12.2% more than a year earlier. For many businesses, online orders now come from several places at once, and each has to be checked, paid, picked, shipped and sometimes returned.
What an order management system does
| Function | What it covers |
|---|---|
| Order capture | Collects orders from websites, marketplaces, stores, EDI and sales reps into one queue |
| Inventory visibility | Shows available stock across warehouses, stores and suppliers in real time |
| Order routing | Decides which location fulfills each order, based on stock, cost and delivery time |
| Fulfillment | Sends pick, pack and ship instructions to warehouses or third-party logistics providers |
| Customer service | Lets agents see, change, cancel or split orders |
| Returns | Manages return authorizations, refunds and restocking |
OMS, ERP and e-commerce platforms
E-commerce platforms such as Shopify, Adobe Commerce and BigCommerce handle the storefront and basic order management for one channel. ERP systems handle finance, purchasing and accounting. An OMS sits between them, coordinating orders and inventory across all channels and locations.
Smaller businesses often don't need a separate OMS: the e-commerce platform or ERP covers it. The signs that one is needed are selling on several channels with shared stock, fulfilling from more than one location, frequent overselling or stockouts, and customer service staff checking several systems to answer "where is my order?"
Choosing one
Check integrations first: the OMS has to connect reliably to your storefronts, marketplaces, ERP, warehouse and shipping carriers. Ask how inventory updates are handled, since slow syncing causes overselling. Look at routing rules, returns handling and how pricing grows with order volume.
Implementation
Most OMS projects are integration projects. Plan the data flows between systems first, test with real order volumes, including peak season levels, and run the new system alongside the old one before switching over.
What IT teams should do
- Map every channel orders come from and every system that touches them.
- Measure how often you oversell or cancel orders because of stock errors.
- Shortlist an OMS only after confirming integrations with your existing platforms.
- Load test with peak-season order volumes before going live.