The essentials
A custom corporate intranet starts at €20,000 excl. tax for a simple portal and ranges from €40,000 to €150,000 excl. tax for a complete solution with workflows and ERP integrations. At a 120-employee industrial SME, a well-designed intranet cut time spent searching for internal information by 6 hours per week, with a 90% adoption rate within two months.
A useless intranet is just another layer teams route around
A corporate intranet is worthless if it becomes a tool teams avoid because it complicates their day-to-day work instead of simplifying it. That’s the classic trap of generic solutions imposed without understanding real usage. Before choosing an architecture, we audit how your teams actually work today, with which tools, and which frictions genuinely slow down their activity.
This type of project goes beyond a showcase site or an e-commerce store: it’s an internal web application, often connected to an existing information system (ERP, CRM, HR, sometimes a decades-old legacy system), with access rights, security and user adoption challenges that have nothing to do with a public website.
What a custom business application covers
| Building block | Description |
|---|---|
| Unified portal | Single entry point for company tools and information |
| SSO and access management | Azure AD, Google Workspace, SAML, OpenID Connect |
| Integration with existing tools | ERP, CRM, HR, legacy (AS400, mainframes) without replacing them |
| Document management and workflows | Approval flows, electronic signature circuits |
Off-the-shelf or custom solution: how to decide
| Criterion | Off-the-shelf intranet (M365, Google Workspace) | Custom intranet |
|---|---|---|
| Initial cost | Low (license + configuration) | €20,000 - €150,000 excl. tax |
| Time to launch | Fast (weeks) | 8-12 weeks for the first usable scope |
| Adaptation to specific business rules | Limited | Total |
| Integrating a legacy system with no modern API | Often impossible without custom development | Native, designed for this case |
| Adoption if usage patterns are atypical | Risk of being bypassed | Built with the teams involved |
| Ideal for | Organizations with standard needs | Heterogeneous IT systems, complex business rules, legacy to preserve |
The question isn’t “custom or not” in the abstract, but whether your current tools (M365, Google Workspace) already cover 80% of the need. If they expose modern APIs and your processes stay simple, extending the existing setup costs less and deploys faster. Custom development becomes relevant once the IT landscape is heterogeneous, complex business rules must be respected without approximation, or a legacy system with no API needs to be integrated as-is.
Who it’s for
- Growing SMEs (30 to 150 employees) whose internal tools have grown in a disorganized way
- Multi-site organizations that need a shared reference system without duplicating processes
- IT departments with a heterogeneous system, especially an old legacy platform that isn’t up for replacement
Our method
- Usage audit: how your teams actually work, not how the org chart says they should.
- Architecture choice: custom-built, an extension of an existing platform (M365, Google Workspace), or a hybrid solution depending on the real context.
- Integration and SSO: secure connection to existing tools with no double authentication for users.
- Rollout and adoption: progressive deployment with change management support, not a big bang.
Budget and timeline
| Scope | Budget | Timeline |
|---|---|---|
| Simple intranet (portal, documents, directory) | Starting at €20,000 excl. tax | 8-12 weeks |
| Complete intranet (workflows, ERP/CRM integrations) | €40,000 - €150,000 excl. tax | Modules delivered in 4-6 week iterations |
Proof by example: integrating without replacing
A French retail player wanted to launch its e-commerce store without touching its AS400 logistics system, in place for fifteen years and considered untouchable by its teams: reliable, well-known, aligned with years of business rules. We built an integration layer that translates exchanges between the modern storefront and the legacy system, with a queuing system that absorbs load spikes and a nightly reconciliation process that catches any discrepancy between the two systems.
Results: revenue up 40% in 6 months, zero undetected stockouts, legacy system preserved intact. The same principle applies to an intranet connected to an ERP or an old IT system: integrate without rewriting, with an abstraction layer that protects the existing system. See the full case study.
FAQ
Do I need a custom intranet or an off-the-shelf solution like SharePoint?
If your needs are standard (documents, directory, internal news) and your current tools (Microsoft 365, Google Workspace) are enough, an off-the-shelf solution costs less and deploys faster. Custom development is justified once your IT system is heterogeneous, you need to integrate a legacy system with no modern API, or your business rules don’t fit a standard mold.
How long does it take to deploy a corporate intranet?
A first usable scope (portal, essential documents, directory) is generally deliverable in 8 to 12 weeks. Additional modules (workflows, ERP/CRM integrations) follow in 4 to 6 week iterations, rather than as a single block that would delay going live.
Can a custom intranet replace our existing ERP?
No, and that’s generally not the goal. A custom intranet integrates with your existing ERP to surface the information your teams need daily, without duplicating or replacing the management system already in place. Replacing an ERP is a separate project, with far greater risks and scope.