The verdict in three sentences
A secure client portal for an accounting firm in London costs between 25,000 and 70,000 EUR in 2026 depending on scope (SSO, document vault, e-signature, automated reminders). Budget 3 to 5 months of development, 150 to 400 EUR/month of EU hosting and 500 to 1,200 EUR/month of maintenance. The 6-to-10-hour weekly saving on document collection pays the project back in 12 to 18 months.
What the development budget covers
The price depends mostly on the number of modules and the security level the profession demands (confidentiality, GDPR, document retention). Here are the 2026 ranges seen across European studios and software houses.
| Module | 2026 range (EUR) | Indicative timeline |
|---|---|---|
| SSO authentication + MFA | 4,000 - 9,000 | 2 - 3 wks |
| Document vault (upload, versioning) | 6,000 - 15,000 | 3 - 5 wks |
| Segregated client spaces + roles | 5,000 - 12,000 | 2 - 4 wks |
| E-signature (eIDAS) | 3,500 - 8,000 | 1 - 2 wks |
| Automated reminders and notifications | 3,000 - 7,000 | 1 - 3 wks |
| Advisor dashboard + audit log | 4,000 - 10,000 | 2 - 4 wks |
| Typical project total | 25,000 - 70,000 | 3 - 5 months |
An 8-person firm typically lands mid-range, around 42,000 EUR, with SSO, vault, signature and reminders.
The recurring costs you must not forget
The portal does not stop at delivery. Sovereign hosting, corrective and evolutionary maintenance and monitoring weigh on the annual budget.
| Recurring item | 2026 monthly cost | Annual cost |
|---|---|---|
| EU hosting (GDPR, optional health-grade) | 150 - 400 EUR | 1,800 - 4,800 EUR |
| Maintenance (fixes, features, support) | 500 - 1,200 EUR | 6,000 - 14,400 EUR |
| Certificate, monitoring, backups | 40 - 90 EUR | 480 - 1,080 EUR |
| E-signature (usage-based) | 0.50 - 1.50 EUR/signature | variable |
| Typical recurring total | 700 - 1,700 EUR | 8,400 - 20,400 EUR |
Mini case study
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Nadia, managing partner of an 8-person accounting firm in London, still collects documents by e-mail and manually chases 120 clients each month. Each staff member loses about 1h15 per day sorting files and chasing clients, roughly 8 hours per week across the operational team.
She invests 42,000 EUR in a portal with SSO, vault and automated reminders, plus 900 EUR/month of maintenance and hosting. By automating collection, the team recovers 8 hrs/week, about 35 hrs/month valued at 45 EUR/hr: 1,575 EUR/month saved, minus 900 EUR of recurring cost = 675 EUR/month net gain. On time savings alone, the 42,000 EUR investment pays back in about 15 months, before counting fewer errors and a premium client experience.
FAQ
What is a realistic minimum to get started? A genuinely secure document-exchange portal (SSO, vault, roles) starts around 25,000 EUR. Below that you get a bare upload space without the confidentiality guarantees a firm needs.
How long until go-live? Budget 3 to 5 months from scoping to launch, including 3 to 4 weeks of specification and testing. A limited MVP (upload + notifications) can ship in 8 to 10 weeks.
Is the portal GDPR and confidentiality compliant? Yes, provided EU hosting, encryption at rest and in transit, an audit log and fine-grained access control. These guarantees represent about 20 to 25 % of the development budget.
Should I prefer an off-the-shelf SaaS at 30 EUR/user/month? For 8 users a SaaS costs about 2,880 EUR/year but limits customization and branding. Custom becomes worthwhile as soon as you want your own workflows and integration with your production software.
What maintenance budget should I plan for year one? Between 6,000 and 14,400 EUR depending on the pace of changes. Year one is usually the busiest (post-launch tuning); it then settles toward the lower end.
Let's scope your project. Tell us your client volume, priority modules (SSO, signature, reminders) and indicative budget, and we will frame a compliant, payback-driven portal. 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.
