The verdict in three sentences
A properly scoped ERP/CRM API integration costs between 8,000 and 30,000 EUR per connector in London in 2026, depending on the complexity of the business objects being synced. The real trade-off isn't the headline price but the choice between point-to-point (cheaper upfront, unmanageable beyond three systems) and middleware (pricier, but scalable). ROI comes from eliminating double data entry: recovering 40 to 80 hours/month is enough to pay back the project in under a year.
What a connector costs in 2026
The price depends on the number of systems, the volume of objects (customers, orders, invoices, stock) and the sync direction (one-way or two-way). Here are the 2026 ballpark figures seen in the London market.
| Integration type | Scope | 2026 price (EUR) | Timeline |
|---|---|---|---|
| Simple one-way connector | Web form to CRM | 8,000 - 12,000 | 4 - 5 weeks |
| CRM to ERP connector | Customers + orders two-way | 14,000 - 22,000 | 6 - 8 weeks |
| Multi-system integration | Site + CRM + ERP + accounting | 25,000 - 30,000 | 8 - 10 weeks |
| Dedicated middleware (iPaaS) | Orchestrating 4+ flows | 30,000 - 45,000 | 10 - 14 weeks |
| Rebuilding a failing connector | Audit + rework | 6,000 - 15,000 | 3 - 6 weeks |
On top of these amounts comes annual maintenance, essential because APIs evolve (deprecated versions, auth changes).
Point-to-point or middleware
Point-to-point links two systems directly. It's fast and cheap for two or three apps, but the number of connections explodes: linking 5 systems point-to-point requires up to 10 links to maintain. Middleware (or iPaaS) centralises flows and cuts complexity.
| Criterion | Point-to-point | Middleware / iPaaS |
|---|---|---|
| Upfront cost (3 systems) | 18,000 - 26,000 EUR | 30,000 - 40,000 EUR |
| Annual maintenance | 15 - 20 % of project | 3,000 - 8,000 EUR + licence |
| Adding a 4th system | +10,000 EUR | +4,000 EUR |
| Flow visibility | Low | Centralised monitoring |
| Break-even point | 2-3 systems | 4+ systems |
Rule of thumb: below three systems, point-to-point is fine. Beyond that, middleware pays off from the second year.
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Mini case study
Mathieu, CIO of a 60-person B2B distribution SME in London, runs an order-entry site, a CRM and an ERP that aren't connected. His reps re-key every order twice: 3 hours/day combined, roughly 63 hours/month. At a loaded cost of 35 EUR/hour, that's 2,205 EUR/month of wasted time, not counting entry errors (around 4 % of orders, with credit notes and returns).
He invests 19,000 EUR in a two-way CRM-ERP connector, plus 3,000 EUR/year maintenance. Annual time savings: 26,460 EUR. The project pays back in under 10 months, and reliable orders also win back the trust of his key accounts.
FAQ
How long does an ERP/CRM API integration take? Expect 4 to 5 weeks for a simple connector, 6 to 10 weeks for a two-way multi-object sync. The timeline mostly depends on the quality of the existing APIs' documentation.
Do I need an iPaaS subscription or custom development? For 2-3 simple flows, custom development avoids recurring licences. Beyond 4 systems or with high volumes, an iPaaS (often 3,000 to 12,000 EUR/year) offers monitoring and resilience.
What happens when an API changes version? That's the role of maintenance (15 to 20 % of project cost/year in point-to-point). Without maintenance, an auth change can stop the sync overnight.
How do you guarantee no data is lost? Through idempotency, queuing and retry mechanisms. A good connector logs every exchange and alerts on failure, rather than failing silently.
Can we start small then extend? Yes, it's even recommended: start with the flow costing you the most in double entry (often orders or customers), then add the others once ROI is proven.
Let's scope your project. Tell us which systems to connect (site, CRM, ERP, accounting), your monthly object volume and your indicative budget, and we'll price the connector or middleware that fits. 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.
