The verdict in three sentences
Integrating an ERP API into a web app costs 8,000 to 30,000 EUR in 2026, the gap driven mostly by how open the ERP is and how many objects you sync. The real risk isn't technical but contractual: API licenses, proprietary connectors and modules billed as extras. Serious scoping of the perimeter and the sync mode prevents 80% of overruns.
What ERP integration costs in 2026
Price depends first on the target ERP and the depth of exchange. A modern ERP exposing a documented REST API (Odoo, recent Sage 100) connects fast; a closed ERP forces middleware or batch export, slower and pricier.
| Scenario | Typical ERP | Objects synced | 2026 cost (EUR) | Timeline |
|---|---|---|---|---|
| Simple read (catalog, stock) | Odoo, Sage | 1-2 objects, one-way | 8,000 - 12,000 | 3-5 wks |
| Two-way sync | Sage 100, Cegid | Customers, orders, invoices | 14,000 - 22,000 | 6-9 wks |
| Complex real-time integration | SAP, Microsoft Dynamics | 5+ objects, webhooks | 22,000 - 30,000+ | 10-16 wks |
| Closed ERP + middleware | AS400, legacy ERP | Via connector/ETL | 20,000 - 35,000 | 12-20 wks |
On top of these come recurring costs: connector maintenance (1,200 to 4,000 EUR/yr, 2026 order of magnitude) and any API license charged by the ERP vendor.
Choosing the right sync mode
Three modes coexist, each with a different cost and reliability profile. The choice drives the architecture and the maintenance budget.
| Mode | Latency | Reliability | Build cost | Best for |
|---|---|---|---|---|
| On-demand REST API | Immediate | High | Medium | Stock, price lookups |
| Webhooks (ERP push) | Near real-time | High with retry | Medium-high | Orders, statuses |
| Scheduled batch (nightly) | Deferred (hours) | Very high | Low | Reporting, large volumes |
The 2026 rule: favor webhooks with a queue and retry for critical flows (orders), and reserve batch for heavy, non-urgent volumes. Always plan for idempotency to avoid duplicate orders during replays.
The hidden costs that blow up the budget
Closed ERPs often bill API access separately. Expect, as a 2026 order of magnitude: a SAP connector module between 3,000 and 8,000 EUR/yr in license, or API calls capped beyond a quota. Other traps: undocumented custom field mapping, a paid test environment, and historical data migration rarely priced upfront.
Mini case study
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Marc, IT director of a B2B distribution SME in Lille, wants his customer portal to show real-time stock and record orders in Sage 100. Scope: read stock/price + write orders, two-way sync. Accepted quote: 17,000 EUR build, 2,400 EUR/yr maintenance. Before integration, 3 sales reps spent 1 hr/day re-keying orders, about 63,000 EUR/yr of time. By automating, the team recovers the equivalent of 2.4 partial FTEs: the project pays back in under 4 months.
FAQ
Do you always need an API to connect an ERP?
No, but it's the most reliable path. Otherwise you go through middleware (ETL) or batch file exports, slower and more fragile. An ERP without an open API typically adds 20-40% to the integration budget.
How long for a standard integration?
Expect 6 to 9 weeks for a two-way customers/orders/invoices sync. SAP or Dynamics real-time projects run to 10-16 weeks depending on the client's ERP team availability.
Who handles sync errors?
A good connector logs each failure, replays automatically, and alerts when blocked. Plan a supervision dashboard: without it, silent errors are costly in manual reconciliation.
Does the ERP vendor charge for API access?
Often yes for proprietary ERPs. Check before signing: a SAP or Dynamics API license can be 3,000 to 8,000 EUR/yr, to factor in from the budgeting stage.
Can we start small and expand later?
Yes, it's even recommended. Begin with one critical flow (stock or orders) read-only, validate reliability, then add objects. This approach cuts risk and spreads the investment.
Let's scope your project. Tell us your ERP, the objects to sync and the flow direction: we'll scope the perimeter and an indicative budget between 8,000 and 30,000 EUR. 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.
