The verdict in three sentences
Double entry between website and ERP is the biggest source of errors and wasted time for an SME selling online. Connecting the two systems delivers 99% stock accuracy, removes order re-keying and speeds up shipping. Two routes: a custom connector at 5,000-15,000 EUR amortised over time, or an iPaaS at 300-900 EUR/month that is faster to launch but recurring.
Custom or iPaaS: which to choose in 2026
The right choice depends on your order volume, the complexity of your business rules and your budget horizon. Here are the 2026 orders of magnitude.
| Criterion | Custom connector | iPaaS (subscription) |
|---|---|---|
| Upfront cost | 5,000 - 15,000 EUR | 500 - 2,000 EUR (setup) |
| Recurring cost | maintenance 15-20%/yr | 300 - 900 EUR/month |
| Complex business logic | Excellent | Limited |
| Sync latency | Real-time possible | 1 - 15 min by plan |
| Break-even point | Pays off > 24 months | Pays off short term |
| Vendor lock-in | Low | High |
Over 3 years, an iPaaS at 600 EUR/month totals 21,600 EUR: beyond a certain volume and flow stability, custom becomes more economical and more performant.
What must be synchronised
A successful ERP integration is not just stock: it covers the full order cycle, from catalogue to invoicing, with solid error handling.
| Synced flow | Direction | Recommended frequency |
|---|---|---|
| Products and prices | ERP to site | Daily or on each change |
| Stock levels | ERP to site | Real-time |
| Orders | Site to ERP | Immediate |
| Status / shipping | ERP to site | On each change |
| Customers / accounts | Bidirectional | Immediate |
| Invoices | ERP to site | On issuance |
Error handling is critical: a queue with automatic retry, failure alerts and a readable log prevent an order from silently vanishing between two systems.
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Mini case study
Sophie runs an agricultural equipment SME in Amsterdam on Odoo, with about 600 orders/month from the website. Before, two people re-keyed orders into the ERP: roughly 25 combined hours/week, with 4% stock errors causing stockouts and returns. The custom connector cost 11,000 EUR plus 1,800 EUR/year maintenance. Re-keying vanished, freeing the equivalent of 0.6 FTE, or about 1,500 EUR/month in payroll. Stock accuracy rose from 96% to 99.3%. Return on investment in about 8 months, not counting fewer customer returns.
FAQ
Odoo or another ERP, does it change the integration? Odoo has a very complete native REST API and is often quicker to connect. Systems like SAP or Exact vary by version and may need middleware, adding 1,000 to 3,000 EUR to the project.
How long to connect site and ERP? A standard project takes 3 to 6 weeks: flow scoping, development, testing on real orders and a phased go-live. Specific business rules (per-customer pricing, discounts) extend the timeline.
Is real-time really necessary? For stock, yes, if you sell low-quantity items: it prevents selling a product already out of stock. For prices or product sheets, a daily sync is usually enough.
What happens if the ERP is down? A well-designed connector queues operations and replays them automatically when the ERP returns. No order is lost; it is simply processed with a slight delay.
Can we start with iPaaS then move to custom? Yes, a common strategy: iPaaS validates the flows quickly, then you switch to a custom connector once volume justifies the investment and lowers the recurring cost.
Let's scope your project. Tell us your ERP, order volume and business rules, and we'll price the connector or iPaaS best suited to your budget horizon. 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.
