The verdict in three sentences
If your team re-keys more than 50 orders a day into your ERP, a custom API connector pays for itself in under 6 months. A realistic 2026 budget is EUR 8,000 to 22,000 (about USD 8,800 to 24,200) for a 6 to 10 week project, depending on the number of flows and the choice between direct API and middleware. The line item everyone forgets is error monitoring: without alerts and a rejection queue, a silent connector costs more than manual entry.
What an ERP connector costs in 2026
Mid-market Sage editions (Sage 100, widely used by US distributors) do not natively expose a modern REST API. There are three routes: the business objects SDK, controlled read and write on the SQL Server database, or a commercial middleware that provides an API layer. Price depends mainly on the number of flows and their direction. Figures below are in EUR; multiply by about 1.10 for USD, and expect New York day rates 20 to 40% higher if you hire locally.
| Scope | Flows covered | Duration | Price excl. tax |
|---|---|---|---|
| Minimal connector | Web orders into the ERP (1 flow) | 6 weeks | EUR 8,000 to 11,000 |
| Standard connector | Orders, customers, stock (3 flows, both ways) | 7 to 8 weeks | EUR 12,000 to 16,000 |
| Extended connector | + invoices, credit notes, customer prices, payments | 8 to 10 weeks | EUR 17,000 to 22,000 |
| Commercial middleware | Licence + configuration | 4 to 6 weeks | EUR 3,000 to 7,000 + EUR 150 to 400/month |
| Annual custom maintenance | ERP upgrades, fixes | Ongoing | EUR 1,500 to 3,000/yr |
| Monitoring and alerts | Rejection dashboard, email or Slack alerts | Included or option | EUR 1,000 to 2,500 |
Middleware looks cheaper upfront, but it imposes its own data model. As soon as your rules leave the standard path (discounts by product family, multiple warehouses, kitted items), configuration drifts and the subscription stacks up over 5 years: EUR 9,000 to 24,000 of licence on top of the project.
Direct API vs middleware compared
| Criterion | Custom direct API | Commercial middleware |
|---|---|---|
| 5-year cost | EUR 15,500 to 37,000 | EUR 12,000 to 31,000 |
| Specific business rules | All | Limited to configuration |
| Vendor lock-in | None (code delivered) | Strong |
| Real time | Yes (webhook) or every 5 min | Often every 15 to 60 min |
| Rejection handling | Dedicated, replayable queue | Varies by tool |
| ERP version upgrades | Your responsibility (maintenance fee) | Included if the vendor keeps up |
| Time to go live | 6 to 10 weeks | 4 to 6 weeks |
Our rule: middleware if your flows are standard and you process fewer than 30 orders a day, direct API above that or as soon as a business rule affects margin.
The flow diagram to sign off before pricing
A good specification fits on one page of flows. For an SMB that sells online and invoices in its ERP:
- Site to ERP: a paid order creates a sales document, creating or matching the customer by tax ID or email.
- ERP to site: available stock syncs every 5 minutes, per warehouse.
- ERP to site: order status (picked, shipped, invoiced) and tracking number.
- Site to ERP: card payment matched to the invoice.
- Monitoring: every failure goes into a rejection queue with its reason, and an alert fires above 3 rejections an hour.
The three classic risks: duplicate customers (define a matching key), sales tax rounding between the site and the ERP (test 50 real baskets), and database locks during nightly backups (schedule a pause window).
Mini case study
David, CFO of a professional equipment distributor in New York, watches his team re-key 150 orders a day from the website into the ERP. It takes 1.5 FTE, with a 3% error rate (wrong price, wrong address, duplicate customer).
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Current cost: 1.5 FTE at EUR 40,000 loaded per year, so EUR 60,000 (in New York the loaded cost is closer to USD 65,000 per FTE, which only improves the case), plus about 1,300 orders in error per year at EUR 25 average handling, EUR 32,500. Total: EUR 92,500 a year.
The standard connector is quoted at EUR 15,000, plus EUR 2,000 of monitoring and EUR 2,500 of annual maintenance. Year one costs EUR 19,500. Freed time (1.2 FTE moved to collections, 0.3 FTE kept for edge cases) and errors falling to 0.3% add up to about EUR 77,000 a year. Payback: under 3 months.
FAQ
Does Sage 100 have an official API?
Not a full REST API out of the box. You use the business objects SDK or an API layer supplied by middleware; Sage's cloud products (Sage Intacct, Sage Business Cloud) do have APIs, but with rate limits around 100 requests per minute.
How long does it take to put a connector live?
Plan 6 to 10 weeks, including 2 weeks of testing on a copy of your ERP company file. The timeline doubles if nobody in-house can sign off the invoicing rules.
What happens when the ERP is upgraded?
Annual upgrades usually need 1 to 3 days of testing and adjustments, covered by a EUR 1,500 to 3,000 yearly fee.
Can Shopify, PrestaShop or WooCommerce be connected too?
Yes, these platforms have APIs and webhooks. Each extra platform adds EUR 3,000 to 6,000 to the project depending on the number of flows.
Do we need a dedicated server?
The connector runs on a small server or container at EUR 20 to 60 a month, close to the ERP server, with a secure tunnel to the website.
Let's scope your project. Describe your flows (orders, stock, invoices) and your daily volume: we will price the connector, monitoring and maintenance with a 6 to 10 week plan. 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.
