Many businesses got their shop after their inventory system - or the other way round. Both run well on their own. In between sits someone who transfers the morning’s orders from the shop into the inventory system, tops up stock levels during the day and writes the tracking numbers back at the end. With a handful of orders that works. As the shop grows, it becomes the bottleneck.
How shop and ERP come together rarely has one answer that fits everyone. It depends on which systems are in place, which one is in charge of which data and how much is moving. Here is what has to travel and which routes exist.
What has to travel between shop and ERP
| Data | Direction | In charge |
|---|---|---|
| Items, descriptions, images | inventory system into the shop; texts and images often in the shop itself | shared |
| Prices and price lists | inventory system into the shop | inventory system |
| Stock levels | warehouse into the shop, continuously | inventory system |
| Orders | shop into the inventory system | the shop creates, the inventory system processes |
| Customers | shop into the inventory system, matched against existing customers | inventory system |
| Shipping status, tracking number | inventory system into the shop, from there to the customer | inventory system |
| Invoices | inventory system into the shop or straight to the customer | inventory system |
| Returns and credit notes | shop into the inventory system, stock back into the warehouse | both |
| Payments | payment provider into the inventory system or the accounts | payment provider |
The table already shows the most important rule: for every kind of data it must be clear which system is in charge. Otherwise shop and ERP overwrite each other, and nobody knows which price applies.
The vendor’s connector or your own interface
For common pairings there are ready-made connectors. Inventory systems with roots in online retail usually come with links to Shopware, Shopify and WooCommerce. For Shopify and WooCommerce there are many extensions that pass orders to accounting or inventory, and services such as Zapier or Make connect a great deal without programming.
A ready-made connector is the first choice if it fits your workflows. Check:
- Does it cover every kind of data you need - including returns, partial deliveries and credit notes?
- Can it handle your particularities: variants, volume pricing, customer groups, several warehouses?
- What happens on an error? Does the order sit there, or does the connector let you know?
- Who maintains it when shop or inventory system are updated?
Your own interface becomes necessary when the connector fails on your rules: prices that arise from customer group and quantity together, items built from components, stock across several warehouses with reservations. Or when the ERP is older and has no connector at all. Whether and how your ERP can be connected is something we clarify up front where possible - not every system gives up its data in a usable form.
Marketplaces on top
If you also sell through Amazon or eBay, you have the same questions a second time - plus the marketplaces’ quirks: their own item mapping and shipping requirements, fees that have to end up in the accounts. Many inventory systems come with marketplace connections. What matters is that every channel draws on the same stock, otherwise you sell one item twice.
Typical stumbling blocks
- Variants: a jumper in several sizes and colours is one item with variants in the shop and a whole series of items in the inventory system. The mapping has to be clean in both directions.
- Price lists: the shop knows one price, the ERP knows customer groups, volume tiers and promotions. Which logic applies in the shop, and where is it maintained?
- Partial deliveries: one order, two parcels. The shop has to understand two tracking numbers and an intermediate status.
- Stock: how often is it reconciled? Stock handed over only overnight leads to sales of goods that are already gone. Reservations from the retail store belong in there too.
- Customers: the guest customer from the shop and the existing customer in the ERP are the same person. Matching by email address alone is often not enough - see the article on master data.
- Tax: sales abroad, different tax rates, small-amount invoices - the tax logic needs agreeing with your tax adviser.
- Payments: PayPal, Klarna or card providers pay out in batches and deduct fees. Matching them to individual orders is manual work unless someone automates it. How the documents reach your tax adviser is covered in the article on the DATEV connection.
Who is in charge: shop or inventory system
Most of the time the answer is: the inventory system is in charge of items, prices, stock and customers, the shop of texts, images and presentation. Orders originate in the shop and belong to the inventory system from the moment they arrive. If you have no inventory system yet and maintain everything in the shop, first clarify whether an inventory system or an ERP is the right choice - because the integration is only as good as the system behind it.
Questions before you decide
- Which kinds of data from the table are handled by hand today?
- Is there a ready-made connector for your pairing of shop and inventory system, and does it cover returns and partial deliveries?
- What is special about your items and prices?
- How many channels sell from the same stock?
- Who notices when an order does not arrive?
If no ready-made connector fits, we build the interface so that shop and inventory system stay as they are.
