The verdict in three sentences
A custom integration API between the website, CRM and ERP of an industrial SME costs 10,000 to 40,000 EUR in Amsterdam in 2026 and 6,000 to 25,000 EUR excl. VAT in Toulouse, depending on the number of flows and the ERP (Sage, Cegid, Odoo, SAP Business One). The iPaaS alternative (subscription middleware) costs 300 to 1,500 EUR a month, with a faster start but a lasting dependency. Either way, the aim is to save 1 to 3 FTE of re-keying and bring the error rate below 0.5%.
The hidden cost of re-keying
In many industrial SMEs, aerospace subcontractors, equipment makers, technical distributors, orders arrive through the website or CRM and are then typed by hand into the ERP. The same goes for invoices, stock and customer records. Manual entry typically produces 2 to 4% errors (quantity, part number, delivery address), each costing a credit note, a return or a customer call. Integration removes double entry: an order approved online automatically creates the ERP order, and ERP stock updates the website.
| Flow to integrate | Direction | Complexity | Indicative 2026 cost (EUR excl. VAT) |
|---|---|---|---|
| Customers and contacts | CRM to ERP | Low | 1,500 to 3,500 |
| Catalog, prices and stock | ERP to website | Medium | 2,500 to 6,000 |
| Orders | Website or CRM to ERP | Medium to high | 3,000 to 8,000 |
| Invoices and credit notes | ERP to CRM and portal | Medium | 2,000 to 5,000 |
| Delivery status | ERP or carrier to website | Medium | 1,500 to 4,000 |
| Monitoring and error recovery | Dashboard, alerts, retries | Essential | 1,500 to 3,500 |
A two-flow connector starts around 6,000 EUR in Toulouse; a full website, CRM and ERP integration with monitoring reaches 20,000 to 25,000 EUR.
Custom connector or iPaaS: comparison
The choice depends on volume, process stability and the ERP's ability to expose a clean API. Odoo and SAP Business One (Service Layer) offer documented APIs; some on-premise Sage or Cegid versions require database access or an intermediate module, which raises the cost.
| Criterion | Custom connector (Toulouse) | iPaaS (subscription middleware) | Nearshore connector (Dakar) |
|---|---|---|---|
| Upfront cost | 6,000 to 25,000 EUR | 1,000 to 5,000 EUR setup | 3,600 to 15,000 EUR |
| Recurring cost | 100 to 300 EUR a month (hosting + maintenance) | 300 to 1,500 EUR a month | 80 to 250 EUR a month |
| 3-year cost (average case) | 18,000 to 30,000 EUR | 15,000 to 50,000 EUR | 11,000 to 21,000 EUR |
| Time to go live | 4 to 10 weeks | 2 to 6 weeks | 4 to 10 weeks |
| Specific business logic | Unlimited | Limited to available connectors | Unlimited |
| Dependency | You own the code | iPaaS vendor | You own the code |
| Amsterdam benchmark | 10,000 to 40,000 EUR | Same iPaaS grid | n/a |
iPaaS suits standard, low-volume flows. Custom wins as soon as business rules are specific (customer-specific pricing, bills of materials, multiple warehouses) or volume exceeds a few thousand transactions a month.
A method with no bad surprises
An integration project runs in four steps. Mapping of flows and fields (1 to 2 weeks): which system owns which data, which code mappings apply. Prototype on one priority flow, usually orders, tested on a copy of the ERP. Hardening: error handling, queueing, automatic retries, a log the order desk can read. Cutover in stages with dual checks for 2 to 4 weeks. Require flow documentation and automated tests: they protect the integration when the ERP is upgraded.
Mini case study
Sophie, CFO of an 80-person mechanical subcontractor near Toulouse, sees her order desk re-key about 60 orders a day from the B2B portal and CRM into Sage. Two people spend most of their time on it, with a 3% error rate generating around forty disputes a month.
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She invests 18,000 EUR in an orders, stock and invoices connector, plus 200 EUR a month of maintenance and hosting. The connector frees 1.5 FTE, about 60,000 EUR a year of loaded cost redeployed to customer service, and brings the error rate down to 0.4%. Avoided disputes are worth about 15,000 EUR a year. The project pays back in under 4 months. A Dutch company with the same scope in Amsterdam would budget 10,000 to 40,000 EUR.
FAQ
How much does an ERP API integration cost in Amsterdam in 2026?
Roughly 10,000 to 40,000 EUR depending on flows and ERP. In Toulouse the range is 6,000 to 25,000 EUR excl. VAT, and a nearshore team in Dakar can deliver for 3,600 to 15,000 EUR.
Is my Sage or Cegid ERP compatible?
Recent cloud versions expose APIs; some on-premise versions need an intermediate module. That case usually adds 2,000 to 5,000 EUR to the project.
iPaaS or custom development?
iPaaS at 300 to 1,500 EUR a month suits standard flows and low volumes. Beyond a few thousand monthly transactions or with specific business rules, custom is cheaper over 3 years.
How long until production?
From 4 to 10 weeks, including 1 to 2 weeks of mapping and 2 to 4 weeks of staged cutover with dual checks.
What happens when the ERP is upgraded?
With automated tests and maintenance at 100 to 300 EUR a month, the connector is checked and adjusted before the upgrade. Without these safeguards, a version upgrade can block flows for several days.
Let's scope your project. Tell us your ERP, connected tools and monthly volumes: we price a connector between 6,000 and 25,000 EUR, in production within 4 to 10 weeks. 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.
