The verdict in three sentences
A custom client portal for a London SME runs between 18,000 and 45,000 EUR (roughly GBP 15,000-38,000) depending on the number of modules (authentication, dashboard, documents, notifications, billing). An MVP built around a single strong promise starts at 12,000 EUR and ships in 10 to 16 weeks. After launch, budget 15 to 20 % of the build cost per year for maintenance, evolution and security.
What each building block of a client portal costs
A portal is not a marketing site: it is an application behind authentication. The budget is assembled module by module. Here are practical 2026 orders of magnitude.
| Module | Scope | Indicative cost (EUR) | Timeline |
|---|---|---|---|
| Authentication + accounts | Login, password reset, roles | 2,500 - 4,500 | 1-2 wks |
| Client dashboard | Summary view, case statuses | 3,000 - 6,000 | 2-3 wks |
| Document space (DMS) | Upload, versions, download | 3,500 - 7,000 | 2-3 wks |
| Email/SMS notifications | Automatic alerts, reminders | 1,500 - 3,500 | 1 wk |
| Billing module | PDF invoices, history, payment | 4,000 - 9,000 | 2-4 wks |
| Admin back-office | Client, content and rights management | 3,500 - 8,000 | 2-3 wks |
Stack 3 to 4 modules and you land naturally in the 18,000-45,000 EUR range, integration and QA included.
MVP or full version: the real trade-off
The right question is not "how many modules" but "what is the one thing that must work at launch". A well-scoped MVP costs two to three times less and validates real usage before you invest.
| Approach | Scope | Budget (EUR) | Timeline | Risk |
|---|---|---|---|---|
| Focused MVP | 1 promise + auth + dashboard | 12,000 - 20,000 | 10-12 wks | Low |
| Standard version | 4-5 modules, back-office | 22,000 - 35,000 | 14-18 wks | Medium |
| Full version | Billing, payment, API | 38,000 - 45,000 | 18-24 wks | High if poorly scoped |
| Maintenance/yr | Security, evolutions, hosting | 15-20 % of build | Ongoing | - |
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Mini case study
Meet Sophie, MD of a 22-person HR consultancy in London. Her clients keep calling to check where their assignments stand. She picks an MVP at 16,500 EUR: authentication, an assignment-tracking dashboard and a document space. Her four consultants spent around 6 hours/week on the phone giving statuses, roughly 210 EUR/week in loaded cost (35 EUR/hr). The portal removes 80 % of those calls: about 8,700 EUR/year saved, an ROI in under 24 months, plus a premium image with her key accounts.
FAQ
What is the minimum budget for a credible client portal? Plan at least 12,000 EUR for an MVP with secure authentication, a dashboard and a document space. Below that you get a disguised brochure site, not a real client area.
How long until go-live? An MVP ships in 10 to 16 weeks; a full version with billing and API reaches 18-24 weeks. The functional scoping phase (2-3 weeks) drives everything else.
What annual maintenance should I expect? Budget 15 to 20 % of the build cost per year, i.e. 2,500 to 9,000 EUR/year depending on size. That covers security, updates, hosting and small evolutions.
Should I go no-code to cut the bill? No-code can work under 8,000 EUR for a simple need, but it hits ceilings fast on security, integrations and scalability. For a multi-client portal with sensitive documents, bespoke stays safer.
Can the portal connect to my billing tool? Yes. An API integration (Xero, QuickBooks, Sage) typically adds 3,000 to 8,000 EUR depending on the target API's maturity.
Let's scope your project. Tell us your 2-3 priority modules and target budget (MVP around 15,000 EUR or a full version) and we'll confirm what ships in 12 weeks. 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.
