The verdict in three sentences
An API integration is not about rebuilding your software; it is about moving data between systems reliably. In 2026, budget EUR 4,000-9,000 for a simple one-way connector and EUR 12,000-30,000 for a bidirectional flow with mapping, idempotency and error recovery. The real cost lies less in initial development than in maintaining third-party APIs, which introduce two to three breaking changes per year.
What an integration costs by flow type
Price depends first on flow direction (one-way or two-way), mode (real time or nightly batch) and required robustness. Pushing orders from a website to an ERP is nothing like real-time two-way stock sync.
| Integration type | Direction | Mode | 2026 price (EUR) | Lead time |
|---|---|---|---|---|
| Simple connector | One-way | Nightly batch | 4,000 - 6,500 | 1-2 wks |
| Simple connector | One-way | Real time (webhook) | 6,000 - 9,000 | 2-3 wks |
| Bidirectional | Two-way | Batch | 10,000 - 18,000 | 3-5 wks |
| Bidirectional | Two-way | Real time + mapping | 18,000 - 30,000 | 5-8 wks |
| Multi-system orchestration | 3+ systems | Hybrid | 30,000 - 60,000 | 8-14 wks |
A senior integrator's day rate in 2026 sits between EUR 500 and 700. A bidirectional connector typically means 20 to 45 person-days depending on the number of fields to map and error cases to cover.
Real time or batch: what drives the price
Real time (webhooks) costs more because you must guarantee idempotency (never process the same event twice), error recovery and a queue. Nightly batch is cheaper but tolerates a delay of several hours.
| Criterion | Nightly batch | Real time (webhook) |
|---|---|---|
| Data latency | 6-24 h | < 30 s |
| Relative cost | Base | +40 to +70 % |
| Idempotency needed | Low | Critical |
| Error recovery | Batch replay | Queue + retries |
| Use case | Accounting, reporting | Stock, payment, availability |
| Server load | Nightly peak | Continuous |
Custom API or iPaaS middleware
A custom-built connector is a one-off cost (plus maintenance), while an iPaaS (Make, Workato, Boomi) is a recurring subscription of EUR 150-1,200/month in 2026 depending on task volume. iPaaS is fast for standard flows; custom wins once transformations are complex or security demands it.
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| Approach | Upfront cost | Recurring cost | Best for |
|---|---|---|---|
| Custom connector | EUR 8,000 - 25,000 | Maint. 150-500/mo | Critical core, high volume |
| iPaaS (SMB) | EUR 0 - 2,000 setup | 150-400/mo | Standard flows, prototyping |
| iPaaS (enterprise) | EUR 5,000 - 15,000 | 800-1,200/mo | Governance, flow catalogue |
The most underestimated hidden cost: breaking changes in third-party APIs. Budget 2 to 3 person-days per year per critical integration to absorb Salesforce, HubSpot or Sage updates.
Mini case study
Claire, CFO of a 40-person industrial SME in Amsterdam, wants to sync her B2B order site with Sage (invoicing) and HubSpot (customer relations). She picks two real-time connectors: site -> Sage (orders and invoices) and site -> HubSpot (contacts). Budget: EUR 16,000 in development plus EUR 350/month maintenance. Previously two people re-keyed orders 3 h/day, roughly EUR 30,000/year of time. The integration pays back in under 8 months, before counting fewer data-entry errors.
FAQ
Do I need to replace my ERP to integrate an API? No, in the vast majority of cases. Sage, SAP, Odoo and Salesforce expose REST APIs or standard connectors; you plug into them without migration, avoiding a six-figure project.
How much is annual maintenance? Budget 10 to 20 % of development cost per year, roughly EUR 150-500/month per connector, plus the 2-3 person-days to adapt to third-party breaking changes.
Webhook or batch: which to choose? Batch for accounting and reporting (they tolerate delay), real time for stock, availability and payments. Real time costs 40 to 70 % more but prevents overselling.
Is an iPaaS cheaper than a custom connector? Over 3 years an enterprise iPaaS at EUR 1,000/month costs 36,000; a custom connector at 18,000 + maintenance runs about 30,000. Custom wins once the volume is stable and critical.
How long does a bidirectional integration take? Usually 5 to 8 weeks for a real-time flow with mapping and error handling, depending on API documentation quality and the number of fields to reconcile.
Let's scope your project. Tell us which systems to connect (ERP, CRM, site), the flow direction and monthly volume, and we will price custom vs 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.
