What Does an ERP Integration Cost? Planning for 2027

The first and usually biggest lever is the number of data objects. Items, prices, stock levels, customers, orders, delivery status, invoices and returns are each separate data flows with their own mapping, their own error handling and their own test cases. An integration that only sends stock levels to the shop and orders to the inventory system is a different project from one that also synchronises customer accounts, documents and returns. Each additional data object adds not only its own development but also its interactions: a return touches stock, order and credit note at the same time.

The second lever is direction. A one-way flow, such as stock from the ERP to the shop, needs a clear source system and a robust transfer. As soon as data flows in both directions, conflict rules come in: what happens if a customer address is changed in the shop and in the ERP almost simultaneously? Which system wins, how does the other one find out, and who cleans up duplicates? These questions cost design time, code and above all test cases. The article on bidirectional synchronisation shows which patterns have proved themselves.

For the budget this means: first write down the list of data objects and their direction, then decide on stages. Many projects sensibly start with items, stock and orders and add documents, returns and customer accounts in a second stage. That spreads the cost over two budget years without the first stage having to be rebuilt later, provided the mapping is designed for the second stage from the outset.

Special logic is a driver that is often missing from early estimates, because it is taken for granted in day-to-day business. In the ERP, a quantity tier for a customer group looks like a row in a table. In the shop, the same rule has to apply at runtime: for the logged-in customer, in the basket, in search and on the invoice. The more such rules there are, the more work moves from mapping into development and from development into testing.

Several of these topics have their own articles, for example on B2B price synchronisation. For budget planning, a simple inventory is enough to start with: which of the six points apply to you, and in how many variations? A few customer groups with one tier each are different from individual contract prices for every single customer, and a handful of pack-size items are different from a range that is sold in several units throughout.

Operations is the only block that does not end at go-live. Shop and ERP keep evolving, certificates expire and legislation changes document rules. Several such dates for 2027 can already be named today. They do not affect every company, but they belong in every budget plan at least as a checked line.

Business Central online receives two major updates per year, with new major versions every April and October (Microsoft Learn). The period in which administrators can reschedule such an update lasts five calendar months (Microsoft Learn). Specific breaks for integrations have been announced: from version 29.0, Microsoft pages can no longer be exposed as SOAP endpoints (Microsoft Learn), and from version 30 in 2027 release wave 1 no longer as OData endpoints either (Microsoft Learn). If your shop integration was built on such pages, plan the move to your own API pages or the standard APIs within this period. Our page on Dynamics 365 integration describes how we connect Business Central via OData endpoints and custom APIs.

At SAP, mainstream maintenance for the core applications of SAP Business Suite 7 ends at the end of 2027 (SAP), followed by optional extended maintenance until the end of 2030 (SAP). If your shop is connected to such a system, migrating the interfaces is a project with its own budget; the article on the end of SAP ECC maintenance sets out the options.

Public TLS certificates issued on or after 15 March 2027 may be valid for no more than 100 days (CA/Browser Forum); from 15 March 2029 the limit drops to 47 days (CA/Browser Forum). Every interface that serves such a certificate therefore needs automated renewal, otherwise certificate changes become a recurring manual task with a risk of outages. The article on shorter certificate lifetimes describes the steps required.

For domestic invoices between businesses in Germany, the transitional rule allowing invoices on paper or, with the recipient's consent, in another electronic format applies in 2027 only if prior-year turnover was no more than 800,000 euros (Section 27(38) UStG). Above that, the issuing system must, as a rule, produce e-invoices unless invoicing takes place via EDI with the recipient's consent. Whether the shop or the ERP writes the invoice is an architecture question covered in the article invoice from shop or ERP; in the budget it appears as an extension of the document flow.

With cloud ERP there is a contractual point as well: from 12 January 2027, providers of data processing services may no longer charge switching fees for the switching process (Art. 29 Data Act). That lowers the fees charged by the previous provider when you switch, but not the effort of moving the interfaces to another system. Whether a specific contract falls under the rule has to be checked case by case. If you are considering a switch, budget the rebuild of the integration as a separate line.

If you roll forward quotes from the previous year, keep an eye on price trends. Producer prices for services as a whole were 3.7 percent (Destatis) higher in Q2 2026 than in the same quarter of the previous year. For the items that make up an interface, the increase was smaller: prices for software development and programming were 0.8 percent (Destatis) above the same quarter of the previous year, prices for software and software licences 1.1 percent (Destatis), and those for data processing, hosting and related services 1.4 percent (Destatis). Besides general cost increases, the companies surveyed also cited higher licence costs as reasons (Destatis).

For planning, the main consequence concerns the recurring items. Licences for connectors, middleware or cloud services are usually billed annually and follow their providers' price adjustments. They therefore belong in a separate line with its own projection, apart from the one-off implementation. That line is also the place to record which licence is tied to which connection, so that it is clear which costs disappear when a channel is switched off.

An integration whose costs can be traced in advance is easier to defend internally. If you know what each block stands for, you can explain in the budget meeting why an item should stay and where a later stage is enough. For monitoring in operation, a middleware with monitoring is worth a look, as it makes data flows visible so that errors are ideally noticed before they reach the customer.