The verdict in three sentences
A custom ERP-CRM API integration in London ranges from EUR 15,000 to EUR 50,000 in 2026 depending on the number of synchronised objects and mapping complexity. Expect a 6 to 14 week timeline and connector maintenance of EUR 300 to 900/month. Below 3 simple flows, an iPaaS (Make, n8n) is often enough; beyond that, custom development becomes more cost-effective and more reliable.
What the integration budget covers
An ERP-CRM integration is not just "plugging two apps together". The cost depends on the number of synchronised entities (customers, products, orders, invoices), the direction (one-way or bidirectional), the frequency (real-time via webhooks or nightly batch) and conflict handling. Here are the 2026 order-of-magnitude figures for the London market.
| Scope | Synchronised objects | Timeline | Price EUR |
|---|---|---|---|
| Simple connector | 1-2 objects, one-way | 3-5 weeks | 15,000 - 22,000 |
| Standard connector | 3-4 objects, bidirectional | 6-9 weeks | 24,000 - 38,000 |
| Advanced integration | 5+ objects, real-time, dedup | 10-14 weeks | 40,000 - 50,000 |
| Multi-source middleware | ERP + CRM + e-commerce | 12-18 weeks | 50,000 - 80,000 |
The day rate for a senior integration developer in London sits between EUR 450 and 700 in 2026. A standard integration therefore represents 40 to 70 person-days, including schema analysis, middleware development, regression testing and technical documentation.
Custom or iPaaS: the real cost comparison
A CIO's central question is not just the entry price, but the total cost over 3 years. An iPaaS billed per task or per volume can explode as flows multiply.
| Criterion | Custom | iPaaS (Make/Zapier/n8n) |
|---|---|---|
| Initial cost | EUR 15,000 - 50,000 | EUR 0 - 3,000 (setup) |
| Monthly cost | EUR 300 - 900 (support) | EUR 20 - 800 (by volume) |
| Volume handled | Unlimited | Per-operation quotas |
| Complex business logic | Full | Limited |
| Vendor lock-in | None (you own the code) | Strong |
| Setup time | 6-14 weeks | 1-4 weeks |
Self-hosted n8n is an interesting middle ground: open source, no per-task billing, but it requires a server and maintenance. For a publisher syncing more than 50,000 records per month, custom development or self-hosted n8n almost always become cheaper than Zapier or Make beyond 18 months.
Mini case study
Claire, CIO of an 80-employee industrial SME in London, was losing 12 hours per week to double entry between her ERP (Sage) and her CRM (HubSpot). Two sales reps manually re-keyed every order. Hidden cost: 12 h x 4.3 weeks x EUR 35 = EUR 1,800/month of wasted time, not counting data-entry errors.
She commissioned a standard bidirectional connector for EUR 31,000, with support at EUR 500/month. Return on investment: (1,800 - 500) x 12 = EUR 15,600 saved in the first year. The connector pays for itself in about 24 months, and reliable data eliminated billing disputes.
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FAQ
How much does a basic ERP-CRM integration cost in 2026?
A simple one-way connector (1 to 2 objects) starts around EUR 15,000 in London. The price climbs as soon as synchronisation becomes bidirectional and real-time.
What timeline should I plan for a standard integration?
Expect 6 to 9 weeks for a bidirectional connector covering 3 to 4 objects, including analysis, development, testing and go-live.
iPaaS or custom development: when to switch?
Below 3 simple flows and 10,000 operations per month, an iPaaS is enough. Beyond that, or if business logic is complex, custom becomes more reliable and cost-effective over 18 to 24 months.
What is the maintenance cost of a connector?
Between EUR 300 and 900/month depending on the number of flows and how often the source APIs change. Third-party APIs evolve, and the connector must keep up.
Can we synchronise in real time?
Yes, via webhooks. This adds around 20 to 30% to the budget compared to a nightly batch sync, but removes delays between the two systems.
Let's scope your project. Tell us about your two systems, the objects to sync and your monthly volume: we will price the right connector, custom or iPaaS. 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.
