The verdict in three sentences
A custom ERP connector costs EUR 5,000 to 25,000 in 2026 depending on the available API, data volume and number of flows to sync. Maintenance at 10-20 %/year is not optional: ERPs evolve and APIs change. The right question is not "what does the connector cost" but "what is double entry costing me today" — usually far more than the project.
Price by ERP and by flow in 2026
Cost varies with the maturity of the ERP's API and the number of business objects to connect (products, stock, customers, orders, invoices).
| Target ERP | API quality | Connector price 2026 (EUR) | Maintenance/yr |
|---|---|---|---|
| Odoo | REST/XML-RPC good | 5,000 - 12,000 | 10-15 % |
| Sage | varies by version | 7,000 - 18,000 | 12-18 % |
| Dynamics 365 | rich API | 8,000 - 20,000 | 12-18 % |
| SAP (S/4, B1) | robust but heavy | 12,000 - 25,000 | 15-20 % |
| Legacy ERP / no API | file export/import | 10,000 - 22,000 | 15-20 % |
The architecture choice (iPaaS vs dedicated connector) changes the cost profile between upfront investment and recurring spend.
| Criterion | iPaaS (Make, Zapier, Talend) | Custom connector |
|---|---|---|
| Upfront cost | EUR 2,000 - 8,000 | EUR 5,000 - 25,000 |
| Monthly subscription | EUR 50 - 800/mo | hosting only |
| High volumes | cost rises fast | controlled |
| Complex business logic | limited | full |
| Vendor lock-in | high | low |
| Best for | simple flows, SMEs | volume, business rules |
The hidden cost of non-integration
Without a connector, an SME re-keys every order into the ERP: 5 to 8 minutes per order, plus errors. At 600 orders/month, that is 50 to 80 hours of data entry, not counting stock-outs from discrepancies and late-issued invoices. It is this recurring cost, not the connector price, that decides the ROI.
Mini case study
Markus, operations director at a 30-person trading SME in Berlin, handles 750 web orders/month re-keyed manually into SAP Business One. Re-keying ties up 1.5 admin FTE and generates about 2 % errors (stock, prices). A custom connector at EUR 16,000 (15 %/yr maintenance) automates the order → ERP → invoicing flow. Result: 1 FTE reassigned (~EUR 42,000/yr loaded), errors down below 0.3 %, and invoices issued same-day. The connector pays for itself in under six months.
FAQ
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iPaaS or custom connector: which to choose?
iPaaS suits simple flows and low volumes (from EUR 2,000 + subscription). Custom becomes profitable as soon as volumes rise or business logic is complex, because the iPaaS subscription climbs with operation count.
Why does maintenance cost 10-20 %/year?
ERPs push updates, APIs evolve and business needs change. Without maintenance, a connector breaks within 12 to 24 months. It is continuity insurance.
How long to build a connector?
Expect 3 to 6 weeks for a modern-API ERP (Odoo, Dynamics), 8 to 14 weeks for SAP or a legacy ERP needing file exports.
What if my ERP has no API?
We use file exchange (CSV, EDI) or an intermediate database. It is more fragile and slightly costlier to maintain, but perfectly viable.
Can the sync be two-way?
Yes: the site pushes orders to the ERP, and the ERP returns stock, prices and statuses to the site. It is the most common scenario in B2B e-commerce.
Let's scope your project. Tell us your ERP, the flows to sync and your order volume, and we'll price the connector and the re-keying cost avoided. 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.
