The verdict in three sentences
For a lighting manufacturer in Amsterdam supplying 60 distributors, a documented partner REST API costs 25,000 to 60,000 EUR, delivered in 8 to 12 weeks, plus 5,000 to 12,000 EUR for a developer portal and 100 to 400 EUR per month for hosting. On the other side, re-keying prices, stock and spec sheets takes about 2 FTEs across your team and your distributors, with pricing errors that eat margin. The project hinges on three often-neglected points: key-based security and quotas, versioning from v1, and documentation that distributors' integrators understand without calling you.
The hidden cost of re-keying at a B2B manufacturer
Today, the sales admin team sends Excel price and stock files every week, answers stock queries by email and shares spec sheets as PDFs. Each distributor re-keys them into its ERP or webshop. The result: prices weeks out of date, discontinued items still being sold and incomplete product pages at resellers.
| Item | Current situation (2026 order of magnitude) | With a partner API |
|---|---|---|
| Preparing price and stock files | 1 sales admin FTE, about 55,000 EUR fully loaded per year | Automated, 2 h of checks per week |
| Answering stock queries | 1 inside sales FTE, about 58,000 EUR | Real-time lookup by distributors |
| Time to roll out a new price list | 2 to 4 weeks | Immediate on approval |
| Pricing errors at distributors | 3 to 5% of lines | Under 0.5% |
| Up-to-date spec sheets at resellers | 60 to 70% | Over 95% |
| Time to onboard a new distributor | 3 to 6 weeks | 1 to 2 weeks with documentation |
2026 budget: what a partner API really costs
Price depends on the number of resources exposed (products, net prices per distributor, stock, spec sheets and images, orders), on the quality of source data in your ERP and on the service level expected.
| Component | Range (EUR) | Timeline | Comment |
|---|---|---|---|
| Read-only catalogue API (products, specs, images) | 25,000 to 35,000 | 6 to 8 weeks | Minimum core, ERP connector included |
| Net prices per distributor and real-time stock | + 8,000 to 12,000 | + 2 weeks | Pricing rules are often complex |
| Order intake via API | + 10,000 to 15,000 | + 2 to 3 weeks | Validation, acknowledgements, statuses |
| Developer portal (docs, keys, sandbox) | 5,000 to 12,000 | 2 to 3 weeks | OpenAPI, examples, usage dashboard |
| Hosting, API gateway, monitoring | 100 to 400 per month | n/a | Depending on traffic and redundancy |
| Maintenance and enhancements | 500 to 1,500 per month | n/a | Updates, integrator support |
2026 estimates for an experienced team in the Netherlands (order of magnitude). The low end assumes an ERP that already exposes clean data.
Security, quotas and versioning: three rules to enforce
Security. Each distributor gets its own API key, or better OAuth 2.0 client credentials, individually revocable. Since net prices are confidential, the API must filter data according to the calling distributor, and every call is logged.
Quotas. Without limits, a distributor with a poorly built sync can send hundreds of thousands of calls per day. An API gateway enforces quotas (for example 10,000 calls per day and 10 per second) and returns clear error codes. Also offer webhooks to notify price and stock changes rather than letting everyone poll in a loop.
Versioning. Plan /v1/ from the start and a written policy: a version stays supported for at least 12 months after the next one ships. Your 60 distributors do not move at the same pace, and breaking an integration means blocking their sales.
Add an auto-generated OpenAPI specification, examples in PHP, Python and JavaScript (the languages of your resellers' sites) and a sandbox with dummy data.
Mini case study
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Sanne, CIO of a lighting manufacturer in Amsterdam, puts the cost of re-keying at 2 FTEs, about 113,000 EUR per year, plus pricing errors estimated at 18,000 EUR per year in credit notes and compensating discounts.
She launches a catalogue API with net prices and stock at 42,000 EUR, a developer portal at 8,000 EUR, hosting at 250 EUR per month and maintenance at 1,000 EUR per month. First-year cost: 50,000 + (1,250 x 12) = 65,000 EUR. If the API frees 1.5 of the 2 FTEs (about 85,000 EUR) and cuts errors by five (14,400 EUR saved), the annual gain reaches 99,400 EUR. Payback: about 8 months. Illustrative scenario to recalculate with your data.
FAQ
REST or GraphQL for a partner API?
REST remains the safest choice in 2026 for distributors with varied technical skills. GraphQL adds 10 to 20% to design cost and assumes more experienced integrators.
Do we need a developer portal in v1?
Beyond 20 partners, yes. A portal at 5,000 to 12,000 EUR saves dozens of support hours and cuts distributor onboarding to 1 or 2 weeks.
How many calls per day should we plan for?
For 60 distributors syncing hourly across 5,000 SKUs, expect 50,000 to 150,000 calls per day without webhooks. With webhooks, volume often drops below 20,000.
Can we expose ERP data without modifying the ERP?
Yes, in most cases. A connector reads the ERP and feeds a dedicated distribution database, which shields the ERP from load and accounts for 5,000 to 10,000 EUR of the budget.
How long should an API version remain active?
At least 12 months after the next version ships, with a deprecation header and an email to partners 6 months before shutdown.
Let's scope your project. Describe your data (ERP, number of SKUs, pricing rules) and your partners, and we will cost the API, developer portal and hosting with a phased 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.
