The online store shows three units in stock, the warehouse shelf is empty, and the customer has already paid. Differences like these appear wherever the same data lives in two systems and people keep it in sync by hand.
ERP integration is a connection that lets your ERP and another system, such as your online store, warehouse management system (WMS), or planning tool, exchange data automatically. Orders, products, stock levels, and customer records move between systems without anyone retyping them, so every system shows the same reality.
Below you'll read why companies connect their systems to the ERP, which three routes are common, and what it takes to keep an integration reliable once it's live. We've built software and integrations for manufacturing, logistics, and healthcare for more than 30 years, and the examples come from that work.
Why you connect your store, WMS, or planning to the ERP
The ERP is the administrative heart of a company. Products, prices, stock, orders, and invoices all come together there. Around that heart grow specialized systems: an online store for sales, a WMS for the warehouse, a planning tool for production or field service, and sometimes a custom application for a process no package covers. Without an integration, someone keeps all those systems aligned by hand.
The most common connections look like this:
- Online store and ERP. Orders, customers, and payments flow into the ERP; stock levels and prices flow back to the store.
- WMS and ERP. The ERP knows what was ordered, the WMS knows what's on the shelf. The integration keeps both views identical, down to the order line.
- Planning and ERP. A sales order becomes a production order or a service appointment, and hours worked and materials used flow back into the books.
- Custom application and ERP. A customer portal or internal app needs current products, prices, and order statuses from the ERP and sends requests back.
Bram is logistics manager at a technical wholesaler with 45 employees. His online store, WMS, and ERP each work fine on their own; only the connection between them is missing. Two staff members retype orders every day, and every week a customer calls about a product that looked available online while the warehouse ran out long ago.
How such a connection works technically, with APIs, webhooks, and file exchange, is covered in our article on API integration. This article is about the question that comes next: which route do you choose, and what do you arrange around it. Our software integration page shows how we approach that question, from first inventory to ongoing management.
Three routes for ERP integration
For almost every connection to the ERP there are three routes. They differ in speed, flexibility, and how much control you keep.
Route 1: the standard connector
Many vendors offer prebuilt connectors between popular packages, for example between a webshop platform and a widely used accounting or ERP package. A connector is often running within days, and the vendor maintains it when either package changes. In return, you accept the fields, the frequency, and the rules its maker designed. This route fits when your process is standard and both packages are widely used.
Route 2: the integration platform or middleware
An integration platform or your own middleware sits between your systems and passes messages along. Each application only talks to that layer. This pays off once three or more systems share data, because translation, logging, and error handling live in one central place. The downside is an extra system to learn and manage, and with an external platform you also depend on its vendor's pricing and roadmap. Our article on middleware explains when that layer earns its place and which forms exist.
Route 3: the custom integration built on APIs
A custom integration is built on the APIs of both systems and follows your rules exactly: your own product codes, pricing agreements per customer, or an approval step no connector knows. This is the route when your process differs from the standard, when one of the systems is custom software, or when you want to own the logic. It takes more building up front and a partner who maintains the integration afterward. Our approach is described on the API development page.
The routes combine well. Many companies use a connector for accounting, a platform for the message flows, and custom work for the one process that sets them apart from competitors. Start with the simplest route that handles your process and only move up once you demonstrably hit its limits.
What ERP integration does for data quality and double work
Once the integration runs, the retyping disappears first. Employees only handle exceptions, such as an order without a valid VAT number. The bigger gain sits in the quality of the data itself.
Every piece of data gets one place where it's created and changed. Products and prices live in the ERP, stock in the WMS, the order in the online store. All other systems read along. Typos disappear, and decisions about purchasing and delivery times rest on current figures instead of last week's export.
The same effect carries through the whole supply chain. For Deron, which applies RFID in the supply chain, we connected product data across the chain: a product recorded once at the source travels along with every scanned pallet and lands correctly in the catalog and the ERP. Every link in the chain works with the same product data and stops keeping its own lists.
An integration does make existing pollution visible. Duplicate customers or outdated products in the ERP flow straight into the online store once the connection is live. Clean up your master data before that moment; the cleanup is often half the work and keeps paying off afterward.
The pitfalls: field mapping, error handling, and ownership
The technology behind an ERP integration is rarely the problem. Projects overrun on three points that teams underestimate up front.
Field mapping. On paper, fields look identical, and in practice they differ just enough. "Customer" is an email address in the online store and a debtor with payment terms in the ERP. Add units, currencies, tax codes, and character limits. The real work sits in the table that records which field goes where and what happens to values that don't fit. At Bram's company, the store had one address field and the ERP had four; that single mapping line took more discussion than all the others combined.
Error handling. Decide up front what happens when the ERP is unreachable during an update, a required field stays empty, or the same order arrives twice. Messages must never disappear silently. They belong in a queue, get retried, and reach a person with a clear notification after a set number of attempts.
Ownership of the truth. If a price differs between the store and the ERP, it must be settled in advance which system is right. Agree per data type which system leads and let the integration overwrite in that direction only. Without that agreement, two systems quietly undo each other's changes, and you find out from an angry customer or an annual report that doesn't add up.
Managing the integration after it goes live
An ERP integration remains software that runs every day and needs attention. Four things should be arranged from day one:
- Monitoring. A dashboard or alert that shows messages are stuck, before the warehouse notices.
- Vendor changes. ERP vendors and platform makers change their APIs and retire old versions. Someone has to follow the release notes and plan updates.
- Growing volumes. An integration that handles 100 orders a day behaves differently at 2,000. Test it again as the company grows.
- One owner. Record who manages the integration, who calls vendors during outages, and who approves changes.
We build ERP integrations as standalone projects and as part of larger custom software, with a team of 30+ engineers in Nijmegen and Sarajevo. We work according to ISO 9001 and ISO 27001, and the people who build an integration keep it running afterward. For software that processes orders every day, that matters as much as the build itself.
Frequently asked questions
What is ERP integration?
ERP integration is a connection that lets your ERP and another system, such as an online store, WMS, or planning tool, exchange data automatically. Orders, products, stock, and customer records stay identical across systems without anyone retyping them.
When is a standard connector enough?
A standard connector is enough when your process is standard and both packages are widely used. If your process differs, with your own product codes, pricing agreements per customer, or extra approval steps, or if one of the systems is custom software, you end up with an integration platform or a custom integration built on APIs.
Can you integrate an older ERP without a modern API?
Yes, almost always, for example through file exchange or direct database access. Those routes need extra care around security and error handling. Sometimes the integration is also the right moment to assess whether the old package still fits the way the company works today.
Who manages an ERP integration after it goes live?
Settle that before the build starts. In practice it works best when the party that builds the integration also monitors and maintains it, with monitoring, a queue for failed messages, and a fixed point of contact. Internally, one owner stays responsible for the agreements about leading systems and changes.
Key points and next step
ERP integration lets your ERP and the systems around it exchange data automatically, so everyone works with the same figures. The essentials:
- Connect your online store, WMS, planning, or custom application to the ERP as soon as people enter data twice.
- Choose from three routes: a standard connector for standard processes, middleware once three or more systems share data, and a custom integration built on APIs when your process differs.
- Agree per data type which system leads, and clean up master data before the integration goes live.
- Reserve most of the time for field mapping and error handling; the standard flow is built quickly.
- Arrange monitoring and one owner for management after the integration is live.
The next step is an inventory: which systems, which data, how often, and which system leads. With more than 30 years of experience and 100+ projects, we're happy to take a look with you. Book a call with our team, and we'll tell you honestly which route fits your situation.
