The verdict in three sentences
A subcontractor extranet — contracts, progress claims, upload of mandatory documents (social-security compliance certificates, professional and civil-liability insurance, company registration) — is built for an Amsterdam construction group for between 40,000 and 105,000 EUR in 2026. The decisive module is automated document compliance: expiry alerts, payment blocking when a document is missing, an audit trail. ROI shows up in avoided document chasing and reduced compliance risk, with a 12 to 20 week timeline.
What a subcontractor extranet contains, and what it costs
Scope revolves around three axes: compliant document management, progress claims and signature. Here are 2026 ranges for the Dutch market.
| Scope | Modules included | 2026 price (EUR) | Timeline |
|---|---|---|---|
| Essential | Contracts + document vault + expiry alerts | 40,000 – 55,000 | 12–14 wks |
| Standard | + progress claims + online approval | 55,000 – 80,000 | 14–18 wks |
| Advanced | + e-signature + accounting integration | 80,000 – 105,000 | 18–20 wks |
| Broad custom | + compliance scoring + field mobile app | 105,000 + | 20 wks + |
Recurring costs stay contained but are essential to compliance.
| Recurring item | 2026 annual cost (EUR) | Note |
|---|---|---|
| Hosting and monitoring | 3,000 – 7,000 | Uptime and backups |
| Maintenance | 15–18 % of build | Fixes + enhancements |
| E-signature | 1,500 – 6,000 | By contract volume |
| Document verification (3rd-party API) | 2,000 – 8,000 | Certificate checks |
| Email/SMS notifications | 1,000 – 3,000 | Automated reminders |
Document compliance: the duty of diligence
A construction principal has a duty of diligence: it must periodically collect social-security compliance certificates and verify the subcontractor's tax and social standing, or face joint financial liability for undeclared work. An extranet that automatically blocks progress claims while documents are expired or missing turns that constraint into a reliable process. Expiry alerts (liability insurance, registration) and a time-stamped audit trail legally protect the group and remove time-consuming manual chasing.
Mini case study
Marc, works director at an Amsterdam construction group, works with 180 active subcontractors. His admin team currently spends ~30 hours/week chasing documents and manually checking certificates. He rolls out a Standard extranet at 72,000 EUR, plus ~12,000 EUR/year of maintenance and hosting. Automated alerts and conditional blocking absorb 70 % of that load, roughly 21 hours/week saved, ~1,000 hours/year. At a loaded cost of 32 EUR/hour, savings reach ~32,000 EUR/year, before counting the sharp drop in joint-liability risk. The investment pays back in under 27 months, with legal security as a bonus.
FAQ
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What does a subcontractor extranet cost in 2026?
Between 40,000 and 105,000 EUR by module. The Standard version with progress claims and online approval sits around 55,000 to 80,000 EUR.
Can the extranet block a payment when a document is missing?
Yes, that is the heart of compliance: progress claims stay blocked while a compliance certificate or insurance is expired, with an automatic alert to the subcontractor.
How long until go-live?
Between 12 and 20 weeks: 12–14 for the essential version, up to 20 with e-signature and accounting integration.
Can it integrate with our accounting or site software?
Yes, via API or connector. Budget 8,000 to 25,000 EUR depending on how open the tools are and the flows (claims, payments, suppliers).
What annual maintenance budget should we plan?
Maintenance runs 15 to 18 % of the build, roughly 11,000 to 15,000 EUR/year for a Standard project, fixes and regulatory updates included.
Let's scope your project. Tell us your number of subcontractors, the mandatory documents you must check and your accounting software, and we'll frame the compliance module and integration. 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.
