The verdict in three sentences
A custom B2B client portal costs between EUR 25,000 and 80,000 excluding VAT in 2026 (roughly GBP 21,000 to 68,000), plus EUR 8,000 to 20,000 if you connect it to your ERP. The project ships in 3 to 5 months and costs EUR 600 to 2,000 a month in support and maintenance. The return on investment comes mainly from fewer inbound calls, around 40% fewer once clients check orders, invoices and documents themselves.
What you are actually buying: the four portal levels
"Client portal" covers very different realities. A CFO who only wants to expose PDF invoices does not have the same budget as an operations director who wants real-time tracking of every order, with roles per site and single sign-on (SSO) through Microsoft Entra ID or Google Workspace.
| Level | Functional scope | 2026 budget (excl. VAT) | Timeline |
|---|---|---|---|
| Document space | Login, invoices and contracts as PDF, downloads | EUR 25,000 to 32,000 | 8 to 10 weeks |
| Order tracking | + order status, delivery notes, history | EUR 35,000 to 48,000 | 3 months |
| Multi-user portal | + SSO, roles (buyer, accountant, admin), multi-site | EUR 50,000 to 65,000 | 4 months |
| Transactional portal | + online ordering, quotes, payment, support tickets | EUR 65,000 to 80,000 | 5 months |
| ERP connection option | Sync with SAP, Sage, Cegid, Dynamics | + EUR 8,000 to 20,000 | + 3 to 6 weeks |
| Mobile app option (PWA) | Notifications, out-of-office access | + EUR 6,000 to 12,000 | + 3 weeks |
The interface is almost never what moves the budget. The drivers are access rights (who sees what, for which client account, on which site) and ERP data quality. A clean ERP with a documented API costs EUR 8,000. A legacy ERP that needs scheduled file exports and reconciliation rules quickly reaches EUR 20,000.
Three-year total cost compared with the alternatives
Before signing, compare the full 36-month cost, licences and maintenance included. A custom portal costs more in year one, but it does not charge you per client user.
| Option | Initial cost (excl. VAT) | Recurring cost | 3-year total (2026 order of magnitude) | Main limitation |
|---|---|---|---|---|
| ERP portal module | EUR 5,000 to 15,000 | EUR 15 to 40 per user per month | EUR 45,000 to 90,000 for 150 users | Rigid UX, cost per client account |
| Generic portal SaaS | EUR 3,000 to 8,000 | EUR 800 to 2,500 per month | EUR 32,000 to 98,000 | ERP integration often partial |
| Custom, order tracking level | EUR 40,000 | Support EUR 800 per month | EUR 69,000 | Upfront investment |
| Custom, multi-user + ERP | EUR 70,000 | Support EUR 1,400 per month | EUR 120,000 | Longer project, needs steering |
| In-house development | 1 full-stack developer at EUR 60,000 loaded per year | Ongoing salary | EUR 180,000 | Single-person dependency |
Support at EUR 600 to 2,000 a month covers secure UK or EU hosting, security updates, monitoring and a small volume of enhancements (4 to 15 days a year depending on the contract). Require UK GDPR-compliant hosting and daily backups with tested restores.
The three decisions that protect your budget
Start with the flow that generates the most calls. In most mid-sized companies, it is "where is my order?" followed by "can you resend the invoice?". A first release focused on those two uses captures most of the avoidable 40% of calls.
Require SSO from day one. Your key accounts will refuse yet another password. Adding SSO later costs 2 to 3 times more than designing it into the initial architecture.
Put reversibility in the contract. Source code, hosting access and documentation must belong to you. That is what separates a lasting asset from a disguised subscription.
Mini case study
Need a professional website?
Kolonell builds websites that attract clients, optimized for the Sénégalese market. Free quote in 2 minutes.
Claire, CFO of a technical supplies wholesaler in London (EUR 12M revenue, 220 active business clients), sees her customer service team handle 1,100 calls a month, 45% of them about order status or invoice copies. Each call takes 6 minutes on average, or 110 hours a month.
She picks an order-tracking portal with a Sage connection: EUR 40,000 + EUR 12,000 = EUR 52,000 excluding VAT, with support at EUR 900 a month. After six months, calls drop by 38%, saving about 42 hours a month. At a loaded hourly cost of EUR 38, the direct gain is EUR 1,600 a month, plus a 4-day reduction in average collection time because invoices are available immediately. Over 36 months, the direct gain covers about 60% of the investment; the rest is offset by released cash and the team's ability to absorb 20% more clients without hiring.
FAQ
How much does a minimal B2B client portal cost in 2026?
A secure document space with invoices and contracts starts around EUR 25,000 excluding VAT. Allow 8 to 10 weeks of work and EUR 600 a month in support.
Must the portal be connected to the ERP?
Without a connection, data has to be loaded by hand, which wipes out most of the gain. The ERP connection adds EUR 8,000 to 20,000 depending on the quality of the available API.
How long before calls visibly drop?
The first effects show from the second month, provided the launch is backed by an email campaign and a tutorial. A 30 to 40% drop is usually observed after 4 to 6 months.
Can the portal be hosted in the UK or the EU?
Yes, on AWS London, Azure UK South or a certified European cloud, for EUR 80 to 400 a month depending on load. Key accounts often require it.
Can payment be staged?
Payment usually follows milestones: 30% on order, 40% at interim acceptance, 30% at go-live.
Let's scope your project. Describe your client flows, your ERP and your number of accounts: we price the portal in releases, from EUR 25,000 to 80,000 excluding VAT, with a 3 to 5 month 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.
