Past a certain size, the ERP leads and the store follows: products, prices and stock come from the ERP, orders and customers flow back. There are three ways to connect them: an off-the-shelf connector, middleware or a custom integration. The right choice depends less on the tech than on one question: which system is the boss of which data?
What flows between store and ERP
| Data | Direction | How often |
|---|---|---|
| Products and master data | ERP → Shopify | On change |
| Prices and wholesale terms | ERP → Shopify | Daily or on change |
| Stock levels | ERP → Shopify | Every few minutes |
| Orders | Shopify → ERP | Instantly |
| Customers and companies | Shopify → ERP, often both ways for B2B | When created |
| Shipping status and tracking | ERP → Shopify | On shipment |
| Invoices | ERP → customer | On shipment |
The most important rule: for every type of data, there is exactly one leading system. Change prices in the ERP one day and in Shopify the next, and within a week you’ve got two versions of the truth.
Three ways to connect
| Off-the-shelf connector | Middleware | Custom integration | |
|---|---|---|---|
| What it is | Plugin or app from the ERP vendor or a third party | A platform between the two systems | Custom-built |
| Effort | Low | Medium | High |
| Flexibility | Whatever the connector can do | High, via rules and mappings | Unlimited |
| Ongoing costs | License | License plus support | Maintenance with every Shopify or ERP change |
| Right for | Widely used ERPs with standard processes | Multiple systems, complex rules | Highly specific processes |
Many inventory management systems popular in German-speaking countries already come with a Shopify integration, or there’s an established connector. Check that first. A custom integration is the last resort, not the first.
5 pitfalls
- Variants don’t match up. In the ERP, every size is its own item; in Shopify, it’s a variant. Without clean mapping via SKUs, you end up with duplicates.
- Stock lags behind. If it only syncs once a day, the store sells what’s long gone. Fast-moving goods need minutes, not hours.
- Taxes and discounts calculate differently. Shopify and the ERP round differently or book discounts differently. Nobody notices until accounting does.
- Errors go unnoticed. An order never arrives in the ERP, and no one notices. Every integration needs an error alert that reaches a human.
- API limits. Shopify limits how many requests can come in per second. If you send tens of thousands of prices at once, you need an integration that accounts for that.
FAQ
When is an ERP integration worth it? When orders are being transferred into the ERP by hand and it takes more than an hour a day. Or when stock levels are regularly off.
Do I need Shopify Plus for this? Not necessarily. Plus has higher API limits, which helps with very large catalogs. Many integrations run on the other plans too.
How long does an integration take? With an off-the-shelf connector, often a few weeks; with middleware or a custom integration, longer. Most of the time doesn’t go into the tech, but into nailing down the data rules.
Have you done this before? Yes, for example for Taiga: 10,000 products migrated from WooCommerce and the ERP connected.