The verdict in three sentences
Integrating a web app with an ERP via API costs, in 2026, between 15,000 and 50,000 EUR, delivered in 2 to 4 months. Middleware or iPaaS (Make, n8n, Boomi, Workato) adds 200 to 900 EUR/month depending on volume and connectors. The payback is not in license savings but in the end of re-keying: zero double entry, zero gap between systems, reliable real-time data.
Cost per connector type
The price mostly depends on the target ERP, the richness of its API and the number of objects to synchronise (customers, orders, invoices, stock).
| Integration type | Complexity | 2026 cost (EUR) | Timeline |
|---|---|---|---|
| Standard REST API (Odoo, Sage 100c) | Low | 15,000 - 25,000 | 2 months |
| SOAP API / SAP connector | High | 30,000 - 50,000 | 3-4 months |
| Real-time two-way sync | High | 35,000 - 50,000 | 3-4 months |
| Batch / nightly export | Low | 12,000 - 20,000 | 6-8 weeks |
| Via iPaaS (low-code) | Medium | 10,000 - 22,000 + sub | 4-6 weeks |
A well-architected integration includes a sync queue, error handling with automatic retry and consultable logs. That is what separates a robust integration from a fragile script.
Monthly running cost (iPaaS / middleware)
| Solution | Operation volume | 2026 monthly cost (EUR) |
|---|---|---|
| Make (Integromat) | Up to 10,000 ops | 200 - 350 |
| n8n self-hosted | Unlimited (infra) | 150 - 300 |
| Workato / Boomi | Enterprise | 500 - 900 |
| Custom middleware | Depends on infra | 250 - 600 |
iPaaS is ideal to start fast; custom middleware becomes cost-effective beyond high volumes or complex business logic.
Mini case study
Karim, IT director of a distribution SME in Rennes (60 employees), wants to connect a new sales portal to his Sage ERP. Without integration, 2 people re-key 80 orders/day into two systems, with a 4% error rate. He invests 28,000 EUR in a two-way API connector + 300 EUR/month of iPaaS.
Result: the 80 orders flow up automatically, zero re-keying. The 2 people recover 3 h/day each, i.e. 6 h/day in total, about 1,320 h/year. Valued at 35 EUR/h, the saving reaches 46,200 EUR/year, before counting the elimination of the 4% errors. The integration pays back in under 9 months, subscription included.
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FAQ
Why an API integration rather than a manual export?
Manual export (CSV) creates gaps, duplicates and time lag. An API syncs in real time or reliable batch, removes re-keying and provides a trace of exchanges.
iPaaS or custom middleware?
iPaaS (Make, n8n) lets you start in 4-6 weeks at lower cost. Custom is justified beyond high volumes, complex transformations or strong security requirements.
How do you handle sync errors?
With a queue, automatic retries and alerts. A failing order is replayed, not lost. This is a line item you should never cut from the quote.
How much does keeping the integration running cost?
Between middleware (200-900 EUR/month) and connector maintenance (10-15% of build cost per year), budget a clearly identified annual running cost from the start.
Is my SAP ERP necessarily more expensive to integrate?
Often yes: SAP APIs (SOAP/IDoc) are more complex than the modern REST APIs of Odoo or Sage 100c. Budget 30,000 to 50,000 EUR versus 15,000 to 25,000 EUR for a REST-API ERP.
Let's scope your project. Tell us your ERP (SAP, Sage, Odoo...), the objects to synchronise and the flow direction, and we'll price the right connector and middleware. Detailed quote within 48h. 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.
