The verdict in three sentences
Building an internal API to expose your ERP data costs 15,000 to 50,000 EUR excl. tax in 2026, depending on the number of endpoints and the required security level. The realistic timeline is 2 to 4 months, including design, authentication, documentation and load testing. Done well, this API becomes the foundation for all future integrations (mobile, e-commerce, BI, partners) and avoids multiplying fragile point-to-point connectors.
What does an ERP API cost in 2026?
Budget depends on the exposed scope, the API style and security requirements. Here are 2026 orders of magnitude.
| API level | Endpoints | Timeline | 2026 cost (EUR excl. tax) |
|---|---|---|---|
| Read-only API | 5-10 endpoints, 1 domain | 4-6 weeks | 15,000 - 22,000 |
| Read/write API | 15-25 endpoints, 2-3 domains | 6-10 weeks | 24,000 - 35,000 |
| Full secure API | 30+ endpoints, advanced auth | 10-14 weeks | 35,000 - 50,000 |
| Public partner API | Portal, quotas, SLA | 14-18 weeks | 50,000 - 70,000 |
Then plan for an annual run of 12 to 18% of the initial cost for hosting, monitoring and enhancements.
The technical deliverables to require in the quote
A serious quote is not just endpoint code. These deliverables determine the API's longevity.
| Deliverable | Why it's critical | 2026 standard |
|---|---|---|
| API style | Interoperability | REST (OpenAPI 3.1) or GraphQL |
| Authentication | Access security | OAuth 2.1 / JWT, API keys |
| Rate limiting | Load protection | Per-key quotas, clean 429s |
| Versioning | No regressions | /v1, /v2, planned deprecation |
| Documentation | Adoption | Interactive Swagger/Redoc |
| Observability | Operations | Logs, traces, metrics, alerts |
| Tests | Reliability | Unit + contract + load |
Mini case study
Karim, CIO of a 120-person distribution company, ran 4 point-to-point connectors between his ERP, his e-commerce site, his BI tool and a field mobile app. Every ERP change broke one or two connectors: about 6 days/year of corrective maintenance, at 550 EUR excl. tax/day, i.e. 3,300 EUR/year, plus service outages. By centralizing on an internal API priced at 32,000 EUR excl. tax, the 4 flows go through a single stable layer. Corrective maintenance drops to 1,500 EUR/year and every new integration project starts 40% faster. The API pays off from the third connected project.
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FAQ
REST or GraphQL for my ERP?
REST (with OpenAPI 3.1) remains the default choice, easy to secure and cache. GraphQL shines when varied clients (mobile, web front) need flexible queries; it adds 10 to 20% complexity and budget.
Should I expose the ERP directly or use an intermediate layer?
Always an intermediate layer (API gateway or dedicated service). Exposing the ERP directly creates dangerous coupling and security holes; the intermediary protects the system and lets you evolve the ERP without breaking clients.
How much do rate limiting and security cost?
Budget 15 to 25% for authentication, quotas and security audit. It is non-negotiable for an API touching sensitive business data.
Can we start small?
Yes: begin with a read-only API on one domain (15,000 to 22,000 EUR excl. tax), validate usage, then extend. This incremental approach limits risk and spreads the investment.
Let's scope your project. Specify your ERP, the domains to expose, the target clients (mobile, e-commerce, partners) and your security requirements, and we'll price the API and its run. 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.
