The verdict in three sentences
A custom client portal in London runs between 20,000 and 45,000 EUR for a usable MVP and 45,000 to 90,000 EUR for a complete platform with SSO and ERP integrations. Plan for 10 to 20 weeks of development and a maintenance retainer of 800 to 2,000 EUR/month to keep the tool alive. The real payoff is operational: a 30 to 50 percent drop in support load within the first months.
What a client portal covers in 2026
A client portal is the space where your B2B customers track orders, download documents (quotes, invoices, delivery notes), review history and open tickets. The value comes from automation: every piece of information self-served is a call or email that no longer lands on your team. In 2026, strong authentication (SSO, 2FA) and real-time ERP sync are baseline expectations, not options.
The typical technical scope includes secure authentication, fine-grained role management, a dashboard, a documents module and integration with your billing system. Each block adds cost but also measurable productivity gains.
Detailed cost lines (2026, order of magnitude)
| Line item | MVP (EUR) | Complete version (EUR) |
|---|---|---|
| Discovery & UX/UI | 3,000 – 6,000 | 6,000 – 12,000 |
| Authentication & SSO/2FA | 2,500 – 5,000 | 5,000 – 10,000 |
| Dashboard & order tracking | 4,000 – 9,000 | 9,000 – 18,000 |
| Documents & billing module | 3,500 – 8,000 | 8,000 – 16,000 |
| ERP / API integration | 4,000 – 10,000 | 12,000 – 25,000 |
| Testing, UAT & go-live | 3,000 – 7,000 | 5,000 – 9,000 |
| Project total | 20,000 – 45,000 | 45,000 – 90,000 |
On top of that come unavoidable recurring costs: hosting 50 to 300 EUR/month depending on traffic and availability requirements, and maintenance 800 to 2,000 EUR/month for fixes, evolutions and security.
Custom build vs off-the-shelf SaaS: the real trade-off
| Criterion | Portal SaaS (subscription) | Custom portal |
|---|---|---|
| Entry cost | 200 – 1,500 EUR/month | 20,000 – 90,000 EUR one-off |
| Customization | Limited to vendor options | Total (your processes) |
| ERP integration | Standard connectors | Custom, real-time |
| Code ownership | No | Yes |
| 3-year cost (base) | 15,000 – 55,000 EUR | 30,000 – 110,000 EUR |
| Time-to-market | 2 – 6 weeks | 10 – 20 weeks |
SaaS wins when your needs are standard and your volume low. Custom takes over as soon as the portal becomes a competitive advantage, your processes are specific, or the number of users makes seat-based pricing costlier than amortizing a build.
Mini case study
Claire, operations director of a 60-person industrial SME in London, receives around 320 customer requests per month (order status, invoice re-sends, delivery tracking). Two people spend the equivalent of 45 hours/month on this, a loaded cost of about 1,400 EUR/month. After an MVP portal at 32,000 EUR, self-service absorbs 40 percent of requests: she saves around 560 EUR/month in support time and frees up commercial capacity. Factoring the effect on retention and avoided errors (estimate), the return on investment lands between 18 and 30 months, after which the portal works for her.
Need a professional website?
Kolonell builds websites that attract clients, optimized for the Sénégalese market. Free quote in 2 minutes.
FAQ
How much does a client portal MVP cost in London in 2026?
A credible MVP (auth, dashboard, order tracking, documents) sits between 20,000 and 45,000 EUR. Price depends mostly on the number of integrations and the granularity of access rights.
What is a realistic delivery timeline?
Plan for 10 to 20 weeks from discovery to production. An MVP focused on a single ERP integration can ship in 10 weeks; a complete multi-flow version trends toward 20 weeks.
What budget should I plan for annual maintenance?
Maintenance represents 800 to 2,000 EUR/month, roughly 10,000 to 24,000 EUR/year. It guarantees security, updates and evolutions; underestimating it weakens the tool.
Custom or SaaS subscription: which is more profitable?
Below 30 users with standard needs, SaaS (200 to 1,500 EUR/month) is often cheaper. Above that, or as soon as your processes are specific, custom typically pays back in 18 to 36 months.
Are SSO and 2FA really necessary?
Yes: once the portal exposes customer and billing data, strong authentication (SSO/2FA) is expected by enterprise clients and sharply reduces incident risk. The extra cost is 2,500 to 10,000 EUR depending on scope.
Let's scope your project. Tell us your customer volume, ERP integrations and target scope (20-45k EUR MVP or 45-90k EUR full platform) and we'll frame the right level. 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.
