The verdict in three sentences
An API connector between an accounting ERP and a reseller portal costs between EUR 8,000 and 20,000 excl. VAT (about USD 8,600 to 21,600) in 2026, plus EUR 50 to 300 per month for the ERP API licence or middleware. A realistic timeline is 6 to 10 weeks, testing included, for stock and price sync every 15 minutes and invoices pushed into the reseller area. The real budget risk is not the code but the quality of ERP data: price lists per customer group, duplicate items and badly defined sales units.
Three possible architectures and their cost
Depending on the version, mid-market ERPs such as EBP, Sage 50 or Business Central offer an API, cloud connectors or direct access to an on-premise SQL Server database. The architecture choice drives both price and robustness.
| Architecture | Principle | Build (EUR excl. VAT) | Monthly recurring | Robustness |
|---|---|---|---|---|
| Official ERP API | REST calls on items, accounts, documents | 10,000 to 16,000 | EUR 80 to 300 (licence and hosting) | High, vendor supported |
| iPaaS middleware (Make, hosted n8n, Boomi) | Configured flows between ERP and portal | 8,000 to 13,000 | EUR 50 to 250 | Medium, depends on quotas |
| Direct SQL Server read + custom service | Agent installed on the ERP server | 12,000 to 20,000 | EUR 40 to 120 (hosting) | Variable, fragile on ERP updates |
| Scheduled CSV export (stopgap) | Files dropped on FTP | 3,000 to 5,000 | EUR 20 | Low, no real time |
| Hybrid API + message queue | ERP API for writes, queue for peaks | 15,000 to 20,000 | EUR 150 to 300 | Very high |
For a distributor with 900 resellers, the official API or hybrid option is the sound choice. CSV exports break down as soon as resellers order in peak season on tight stock.
What a well-built connector contains
A serious estimate details each flow, its direction and frequency. This is the table you should require in a quote.
| Flow | Direction | Frequency | Estimated effort |
|---|---|---|---|
| Items and families (6,000 SKUs) | ERP to portal | Hourly + delta | 4 to 6 days |
| Stock per warehouse | ERP to portal | Every 15 minutes | 3 to 4 days |
| Prices per reseller tier and volume discounts | ERP to portal | Every 15 minutes | 4 to 7 days |
| Reseller orders | Portal to ERP | Real time (under 1 minute) | 4 to 6 days |
| Invoices and credit notes as PDF | ERP to portal | Hourly | 2 to 3 days |
| Outstanding balance and credit limit | ERP to portal | Every 15 minutes | 1 to 2 days |
| Logs, alerts and error recovery | Cross-cutting | Continuous | 3 to 5 days |
With a day rate of EUR 550 to 750 for a senior developer (Dublin rates often reach EUR 700 to 900), you land in the EUR 8,000 to 20,000 range. Error handling is often missing from cheap quotes: without logs or alerts, an order blocked by a non-existent item code stays invisible until the reseller complains.
Prepare the data before writing a line of code
One to two weeks of clean-up in the ERP prevent most production incidents. Merge duplicate account records, check that every reseller belongs to a price tier, harmonise units (piece, carton, 100 m roll for drip irrigation hose) and set a clear rule for end-of-line items. This step costs EUR 1,500 to 3,000 when supported, but it sharply reduces testing time.
Mini case study
Nathalie is CFO of an irrigation equipment distributor with 900 resellers. Three assistants re-key about 120 emailed orders a day and answer availability requests, i.e. 2.5 FTE tied up. The selected connector costs EUR 15,000 excl. VAT, plus EUR 200 per month.
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- Re-keying time removed: about 1.5 FTE, i.e. EUR 54,000 fully loaded per year
- Input errors avoided (2% of orders at EUR 60 average handling cost): EUR 3,700 per year
- Recurring cost: EUR 2,400 per year
- Net annual gain: EUR 55,300, payback in just over 3 months
The assistants are reassigned to key account follow-up and quote chasing, which improves conversion in peak season.
FAQ
Do we need to upgrade our ERP version?
Not always. Recent editions expose exchange services; a version more than 5 years old may require an upgrade costing EUR 1,500 to 4,000 before the project.
Is a 15-minute sync enough?
For stock, yes in 90% of cases. For orders we target under one minute, and stock is reserved as soon as the order is confirmed in the portal to avoid double selling.
What happens if the ERP is down?
Orders are queued and replayed automatically when the service returns. An alert is sent after 10 minutes of downtime.
Who maintains the connector after an ERP update?
A maintenance contract of EUR 150 to 400 per month covers testing after each major update and fixes. Without it, plan 2 to 3 days of work per year.
Can we also connect logistics and the e-commerce site?
Yes, the same architecture accepts other flows. Each new flow usually costs EUR 2,000 to 5,000 excl. VAT once the foundation is in place.
Let's scope your project. Tell us your ERP version, number of SKUs and resellers: we will price the connector between EUR 8,000 and 20,000 excl. VAT, delivered in 6 to 10 weeks. 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.
