The verdict in three sentences
When an SMB re-keys the same data into 3 to 5 software tools, the hidden cost reaches 0.5 to 1 FTE, or 20,000 to 45,000 EUR a year fully loaded. An iPaaS (Make, Zapier, hosted n8n) at 50 to 600 EUR a month is enough for a few simple flows, but shows its limits above 10,000 operations a day or as soon as errors must be handled properly. A custom API documented with OpenAPI (12,000 to 35,000 EUR excl. VAT, 6 to 12 weeks) becomes the right choice when flows are critical to invoicing or logistics.
iPaaS, custom API or re-keying: the 2026 comparison
| Criterion | iPaaS (Make, Zapier) | Custom API | Manual re-keying |
|---|---|---|---|
| Upfront cost | 0 to 3,000 EUR (setup) | 12,000 to 35,000 EUR | 0 EUR |
| Monthly cost | 50 to 600 EUR depending on volume | 150 to 400 EUR maintenance | 1,700 to 3,700 EUR (0.5 to 1 FTE) |
| Volume supported | Capped by operation tiers | Sized for your peaks | Limited by people |
| Error handling | Basic, manual retry | Logging, automatic retry, alerts | Entry errors of 1 to 4% |
| Legacy business software | Connectors often missing | Database, file or API connection | Always possible |
| Documentation | Visual scenarios | OpenAPI, versioned | None |
| Lock-in | Vendor and its pricing | Code you own | People |
2026 iPaaS pricing is tiered by operations: a scenario syncing 500 orders a day with 8 steps uses 120,000 operations a month, pushing you to the 300 or 600 EUR monthly plans.
What a well-built integration API includes
The API becomes the backbone between your CRM (HubSpot, Salesforce, Pipedrive), your ERP (Sage, Odoo, Exact, NetSuite), your e-commerce site and your logistics provider. Each piece of data has a single source of truth.
| Package | Scope | Indicative 2026 budget |
|---|---|---|
| Scoping and flow mapping | Sources of truth, transformation rules, frequencies | 1,500 to 3,500 EUR |
| REST API core | Authentication, OpenAPI documentation, versioning | 3,000 to 7,000 EUR |
| Connectors (per tool) | CRM, ERP, website, logistics | 2,000 to 6,000 EUR each |
| Webhooks and message queues | Real-time events, decoupled systems | 1,500 to 4,000 EUR |
| Logging and error recovery | Logs, replay, email or Slack alerts | 1,500 to 4,000 EUR |
| Testing and acceptance | Automated tests, datasets, cutover | 1,500 to 3,500 EUR |
Typical plan: 1 to 2 weeks of scoping, 4 to 8 weeks of development, 1 to 2 weeks of acceptance and cutover. Maintenance (150 to 400 EUR a month) covers hosting, monitoring, vendor API changes and fixes.
The real cost of re-keying
| Item | Assumption (40-employee SMB) | Estimated annual cost |
|---|---|---|
| Re-keying orders and customers | 0.6 FTE at 42,000 EUR fully loaded | 25,200 EUR |
| Invoicing errors | 2% of 6,000 invoices, 60 EUR to fix | 7,200 EUR |
| Shipping delays | 150 orders a year, 40 EUR goodwill gesture | 6,000 EUR |
| Stock reconciliations | 4 hours a week | 5,000 EUR |
| Total | 43,400 EUR (about 47,000 USD) |
Mini case study
Joost, managing director of an equipment wholesaler in Amsterdam, uses HubSpot, Exact Online, a WooCommerce site and his logistics provider's portal. Two assistants re-key orders, 0.8 FTE at 42,000 EUR fully loaded, so 33,600 EUR a year. iPaaS option: 450 EUR a month, but his warehouse portal has no native connector and errors block flows without alerts. Custom API option: 22,000 EUR plus 250 EUR a month, or 25,000 EUR in year one. By removing 0.7 FTE of re-keying (29,400 EUR a year), both people move to customer service and the project pays back in 9 months. A Dublin SMB with the same stack would see similar figures.
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FAQ
Do we really need a custom API?
No, if you have 2 or 3 simple flows and fewer than 10,000 operations a month, an iPaaS at 50 to 150 EUR a month is enough. Custom is justified for critical flows, high volumes or software without connectors.
Can our legacy software be connected?
Yes, even without an official API, through read-only database access, scheduled file exports or ODBC. This kind of connector costs 3,000 to 6,000 EUR.
What happens when a vendor changes its API?
Maintenance includes monitoring announced changes and updating connectors. Allow 1 to 3 days of work per major change, usually covered by the 150 to 400 EUR monthly plan.
How long until the first flow is in production?
The first flow, often order sync, can be live in 4 to 6 weeks. All flows are delivered in 6 to 12 weeks.
Do we own the code?
Yes, the source code, OpenAPI documentation and hosting access are handed over to you. Another provider can take over the project without lock-in.
Let's scope your project. List your software tools and the data you re-key: we price an integration API between 12,000 and 35,000 EUR, delivered in 6 to 12 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.
