The verdict in three sentences
An API integration between an ERP and a web application costs between 8,000 and 30,000 EUR in 2026, depending on the number of flows and real-time requirements. The most underestimated line item is not connector development but business acceptance testing and connector maintenance against ERP version upgrades. Expect 4 to 10 weeks from scoping to production, and budget a recurring cost from the initial quote.
What drives the price
The cost of an integration is never just about lines of code. It breaks down by flow (items, customers, orders, stock, invoices), by synchronization direction, and by exchange mode. A nightly batch flow is far cheaper than a real-time bidirectional flow requiring conflict handling, queuing, and replay.
| Line item | 2026 range (EUR) | Comment |
|---|---|---|
| Scoping and data mapping | 1,500 - 4,000 | Workshops, field dictionary |
| Simple flow connector (batch) | 1,200 - 3,000 | E.g. downward item catalog |
| Real-time flow connector | 3,000 - 7,000 | Bidirectional, conflict handling |
| Middleware / iPaaS (setup) | 2,000 - 8,000 | If using an orchestration layer |
| Integration acceptance testing | 2,000 - 6,000 | Test data, edge cases |
| Documentation and handover | 800 - 2,000 | Runbook, architecture diagrams |
Direct API or middleware
Two architectures dominate in 2026. A direct API links the app to the ERP point-to-point: cheaper to set up, but fragile as flows multiply. Middleware (or an iPaaS like Mulesoft, Boomi, or an in-house layer) centralizes orchestration, logging, and replay: costlier upfront, but far more economical beyond three or four flows.
| Criterion | Direct API | Middleware / iPaaS |
|---|---|---|
| Upfront cost | 8,000 - 15,000 EUR | 15,000 - 30,000 EUR |
| Timeline | 4 - 6 weeks | 6 - 10 weeks |
| Annual maintenance | 1,500 - 4,000 EUR | 3,000 - 8,000 EUR + license |
| Ideal flow count | 1 to 3 | 4 and above |
| Error traceability | Limited | Centralized logging |
| Automatic replay | To be coded | Native |
Mini case study
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Thomas, IT director of a 90-employee industrial SME in Nantes, wants to connect his new production-tracking app to his Sage ERP. Three flows: items (downward, batch), work orders (real-time, upward), stock (real-time, bidirectional). Chosen quote: scoping 3,000 EUR, two real-time connectors 12,000 EUR, one batch 2,500 EUR, testing 4,000 EUR, i.e. 21,500 EUR over 8 weeks. Double data entry cost his teams about 15 hours per week, i.e. 780 hours a year at a 35 EUR loaded hourly cost = 27,300 EUR/year saved. Payback in under 10 months, maintenance included.
FAQ
How much is annual ERP integration maintenance? Budget 15 to 20% of the initial cost per year, i.e. 1,500 to 6,000 EUR depending on architecture. ERP version upgrades are the main cause of connector breakage.
Is real-time always required? No. Many flows (catalog, pricing, reference data) work fine as a nightly batch, halving the connector cost. Reserve real-time for stock and orders.
How long does the project take? From 4 weeks for a simple integration to 10 weeks for several bidirectional flows with middleware. Scoping and testing often make up half the schedule.
What if the ERP has no modern API? You use an exchange layer (files, intermediate database, specific connector). This adds 2,000 to 5,000 EUR but is feasible on nearly all ERPs on the market.
Can we start small? Yes, it is even recommended: one critical flow in production first, then extension. This spreads the budget and validates the architecture before investing more.
Let's scope your project. Tell us your flows (source ERP, target app, real-time or batch) and an indicative budget, and we will propose a costed architecture. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.
