The verdict in three sentences
A custom client portal in London runs between EUR 14,000 and 65,000 in 2026, the price driven mostly by the number of modules (authentication, documents, billing, order tracking). A usable MVP starts at EUR 18,000 and ships in 6 to 8 weeks; the full version climbs to EUR 45,000-65,000 over 4 to 5 months. The real cost driver is not the design but the integrations with your existing systems (ERP, billing, transactional email).
Price grid by module (2026, EUR)
Each brick is priced separately: you only pay for what your clients need. The ranges below reflect a mid-tier London agency.
| Module | Price EUR | Lead time |
|---|---|---|
| Authentication + account management | 3,500 - 6,000 | 1 wk |
| Document space (upload, versions, filing) | 4,000 - 8,000 | 1.5 wk |
| Billing + online payment | 6,000 - 12,000 | 2-3 wk |
| Order tracking / support tickets | 5,000 - 10,000 | 2 wk |
| Dashboard + notifications | 3,000 - 7,000 | 1.5 wk |
| ERP / third-party API integration | 4,000 - 15,000 | 2-4 wk |
| Design system + custom UI | 4,000 - 9,000 | 2 wk |
A typical portal combines authentication, documents and tracking: budget EUR 20,000 to 30,000 excluding heavy integrations.
MVP vs full version
The decisive choice is to start with an MVP that proves value before investing in advanced modules.
| Criterion | MVP | Full version |
|---|---|---|
| Budget EUR | 14,000 - 22,000 | 45,000 - 65,000 |
| Lead time | 6 - 8 weeks | 16 - 20 weeks |
| Modules | Auth + docs + basic tracking | All modules + billing + AI |
| Target users | 1 profile | 3-4 distinct roles |
| Integrations | 0 to 1 | 3 to 5 |
| Hosting/month | 40 - 90 EUR | 150 - 400 EUR |
Managed hosting (Vercel + Postgres + storage) costs EUR 40-90/month for an MVP and EUR 150-400/month in high-traffic production, including backups and monitoring.
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Mini case study
Sarah, COO of a logistics firm in Rotterdam (42 staff) wants to kill the 30 daily emails from clients chasing invoices and delivery notes. She picks an MVP at EUR 19,000: authentication, document space and order tracking, delivered in 7 weeks. The portal handles 220 requests/month previously done by hand. At 8 minutes saved per request and a loaded cost of EUR 28/hour, the saving is 220 x 8/60 x 28 = EUR 821/month, or EUR 9,856/year. The MVP pays for itself in about 23 months, before counting fewer disputes and a more professional image.
FAQ
What is the realistic minimum price for a client portal in London in 2026? Around EUR 14,000 for a single-role MVP with authentication, a document space and a simple dashboard, shipped in 6 weeks. Below that you are looking at limited no-code, not true custom.
How much is annual maintenance? Budget 15 to 20% of the build cost per year, i.e. EUR 3,000 to 12,000/year, covering fixes, security updates and small enhancements.
Can the portal connect to our ERP (Sage, SAP, Odoo)? Yes, via API or middleware. Each connector costs EUR 4,000 to 15,000 depending on API richness and data volume to sync.
How long until go-live? A reliable MVP is live in 6 to 8 weeks; a full multi-role platform with billing takes 4 to 5 months including QA and hardening.
Do we need to build everything at once? No. The best approach is an EUR 18,000 MVP, measure real usage, then progressively add the highest-value modules to smooth the investment.
Let's scope your project. Tell us your user roles, your system integrations and your target budget: we frame an MVP deliverable in 6 to 8 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.
