The verdict in three sentences
Connecting your systems by API removes double entry and the re-keying errors that pollute your data. In 2026, budget EUR 15,000-50,000 for a robust integration with middleware and error handling, plus an iPaaS at EUR 500-2,000/month if you do not build custom. ROI hinges on the 8-15 hours/week of entry saved.
Cost of an ERP-CRM-billing integration
2026 order of magnitude, ex-VAT, to connect 3 Toronto systems.
| Approach | Upfront cost | Recurring cost | Timeline |
|---|---|---|---|
| iPaaS (Make, Zapier, n8n) | EUR 3,000-12,000 (setup) | EUR 500-2,000/month | 3-6 weeks |
| Custom API integration | EUR 15,000-50,000 | EUR 200-600/month (hosting) | 2-4 months |
| Native vendor connectors | EUR 2,000-8,000 | included in licence | 1-3 weeks |
| Dedicated middleware (ESB) | EUR 40,000-100,000 | 15-20 %/yr | 4-6 months |
For a mid-market firm, custom API integration or iPaaS cover 90 % of needs. Dedicated middleware is only justified with high volumes or more than 5 systems to orchestrate.
The ROI of killing double entry
The gain is measured in freed admin time and data reliability.
| Gain item | Before (manual) | After (API) | Gain |
|---|---|---|---|
| Order entry | 10 h/wk | 1 h/wk | 9 h/wk |
| Invoice reconciliation | 5 h/wk | 1 h/wk | 4 h/wk |
| Entry error rate | 4-6 % | < 0.5 % | -90 % |
| Quote-to-invoice delay | 3-5 days | real time | -80 % |
| Annual entry cost | ~EUR 28,000 | ~EUR 6,000 | EUR 22,000/yr |
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Mini case study
Sophie, CFO of a 60-person trading mid-market firm in Toronto, runs ERP, CRM and billing in silos. Her teams re-key each order into three tools: 13 hours/week combined, about 620 h/yr at EUR 35/h = EUR 21,700/yr of admin time, before errors. Kolonell custom API integration quote: EUR 32,000 + EUR 400/month hosting, i.e. EUR 4,800/yr. Year-1 cost: EUR 36,800; gain: EUR 21,700 + reduced credit notes and disputes estimated at EUR 8,000/yr = EUR 29,700/yr. Payback: about 15 months, then EUR 29,700/yr of recurring net gain. Verdict: integration approved.
FAQ
iPaaS or custom development? iPaaS (Make, Zapier, n8n) is faster and cheaper to launch, but its monthly cost climbs with volume. Custom costs more upfront but becomes cheaper at high volume and is yours to keep.
How long to connect 3 systems? Budget 2-4 months for a robust custom API integration in 2026, including error handling, logs and testing. A simple iPaaS can be set up in 3-6 weeks.
What happens if an API goes down? A serious integration includes a queue, automatic retries and alerts. Without this error handling, an API outage creates incomplete data that is hard to recover.
Do my current tools need APIs? Yes: most modern ERPs/CRMs expose a REST API. For legacy tools without an API you sometimes need a database connector or a scheduled export/import, which raises the cost.
Is the time saving durable? Yes, as long as the flows are stable. The main risk is an update to one tool breaking the connector: hence the value of the EUR 200-600/month maintenance contract.
Let's scope your project. List your systems to connect (ERP, CRM, billing), the volumes and current entry time, and we will price the integration and its ROI. 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.
