What is ecommerce ERP integration: how an order comes off stock

In a business without integration, someone opens the store panel in the morning, types the overnight orders into the ERP one by one, then checks the warehouse count and corrects the site's stock by hand. While the business is small this works. As orders grow, so do typos, delays, and forgotten orders. The information an integration carries splits by direction:

• From the store to the ERP: the order, customer details, payment status.
• From the ERP to the store: stock level, price, product information.
• Both ways: order status, shipment tracking details, returns, and cancellations.

Integration is less a software feature than an agreement: two systems agree on which information they share, in what order, and under which rules. Integrations where the agreement is not written down turn into arguments about who is right at the first problem.

The scope of the integration should be set at the start too: will only orders move, or customer records, price lists, and campaign prices as well? As the scope widens, the matching rules multiply.

Everything starts with matching. The product code in the store and the stock card code in the ERP must be the same. The spice producer's "chilli flakes, medium hot, half a kilo" is a variant on the site but a separate stock card in the ERP. If the variant and the stock card do not match, the order reaches the ERP but never touches stock. Where a stock card in a separate program falls short is covered in stock cards and the ERP.

Then there is the unit difference: a pack on the site, a box in the warehouse, kilograms in the ERP. If the unit conversion is not defined, the order lands on the right product but the wrong quantity comes off stock. Sending stock back to the store is the other end of the chain; when the warehouse is down to its last pack, the site should show its last pack too.

If the match is right, there are two approaches. Some businesses reserve the quantity as soon as the order comes in and deduct it on shipment; others deduct straight away. Reserving stops stock from looking wrong for orders whose payment is not yet confirmed or that may be cancelled. Which one you choose depends on how your accounting and warehouse work.

Example scenario: Picture a campaign night before a holiday. The last box in the warehouse is sold on the site; if the same box is promised that afternoon to a grocer who calls by phone, someone has to call one of them in the morning and apologise. The sale itself is fine; what fails is the two separate stock records.

Returns slip in the same way. The customer sends the product back, the store processes the return, but in the ERP stock and the account stay as they were. At month end, accounting puts the store report next to the ERP report and spends days looking for where the difference came from.

The manual setup has a hidden cost too: the time of the person typing orders by hand. During campaigns this work stretches late into the night, and the risk of error grows with fatigue.

Once the integration is running, comparing the two sides in the first weeks is a good habit: when the day closes, does the order list in the store match the order list in the ERP?

If you sell on marketplaces as well as your own site, the same stock is sold through more than one channel. Each channel's orders should reach the ERP under the same matching rules; otherwise a sale in one channel does not update another channel's stock. For this reason some businesses set aside part of their stock per channel.

On the accounting side, marketplace sales are different too: the marketplace, not the customer, pays you, after deducting commission and shipping. If those deductions are not recorded separately in the ERP, the account and the bank movement will not match.

Each marketplace has its own rules for order status, shipping, and returns. If the integration does not map these statuses to the ones in the ERP, an order shows as shipped on one side and in preparation on the other. Marketplace payments also often arrive not on the day of the order but in periodic batches; matching which order was settled by which payment is a separate job for accounting.

• Are product codes the same in the store and the ERP, and how are variants matched?
• Which is the source of truth for stock: the ERP or the store?
• Does data move in real time or at set intervals?
• Where does an order that failed to transfer show up, and who is told?
• In which direction, and on which record, do returns and cancellations flow?
• On which side is the invoice prepared, and as what type of document?

The last question touches tax rules; confirm with your accountant which document should be issued. The question about orders that fail to transfer is the one most often skipped: if the integration stops quietly, nobody notices until a customer asks where their parcel is. If the party that builds the integration is not the one that runs it, whom to contact when something breaks should be written down too. Who hears first in the morning when the transfer stopped overnight is the answer to that question.

After ordering, the spice producer's customer asks about the parcel on WhatsApp and a week later asks for a wholesale price. These conversations belong to the customer relationship, not to the ERP. We explained the split between the two in detail in the CRM vs ERP difference article.

That is why the customer relationship side should not be left outside the integration. When the parcel question, the return request, and the wholesale price request sit on the same customer's record, who to offer what in the next campaign can be read from that record too.

We do not present Corex360 as an ecommerce or marketplace integration tool. Corex360's core keeps customers, quotes, contracts, invoices, staff, and files on the same record, and WhatsApp, Instagram, and web conversations land on the customer card through a single inbox. You can see this setup on the bring your channels into one inbox page.

Corex360 is not presented as a stock, order or marketplace integration program; taking an order off stock is the job of your e-commerce platform and your ERP. The customer's WhatsApp, Instagram and web chat land in one inbox in the Messaging window, and the source of the opportunity is kept on the record. The quote form on the website opens an opportunity card automatically. The sales invoice is issued in the Accounting module. Corex360 has an API for exchanging data with external systems.