The verdict in three sentences
A custom client portal for an accounting firm costs between 18,000 and 45,000 EUR in 2026, versus an exchange module that is often bundled but limited inside your practice software. Custom pays off when you want a branded experience, a structured DMS, e-signature and unified SSO. Below 30 active clients the module is enough; above that, the portal becomes an asset that cuts chasing and protects confidentiality.
What a client portal actually funds
A portal is not a shared drop box. It orchestrates document collection, automatic filing into a DMS, signing of engagement letters and returns, and secure multi-user access. Here is a median 2026 budget breakdown.
| Line item | 2026 range (EUR) | Note |
|---|---|---|
| Discovery & UX | 2,500 - 5,000 | Client journey, DMS tree |
| Authentication & SSO | 2,000 - 4,500 | MFA, single sign-on |
| DMS & auto-filing | 4,000 - 9,000 | Tags, OCR, search |
| E-signature | 2,500 - 6,000 | eIDAS integration (Yousign, Docusign) |
| Notifications & reminders | 1,500 - 3,500 | Emails, automatic nudges |
| Practice software integration | 3,000 - 8,000 | API into production tool |
| QA & go-live | 2,500 - 5,000 | Testing, training, GDPR |
| Total | 18,000 - 45,000 | By scope |
Custom vs the bundled module
The real question is not the sticker price but the full three-year cost, chasing and brand image included.
| Criterion | Bundled module | Custom portal |
|---|---|---|
| Upfront cost | 0 - 3,000 EUR | 18,000 - 45,000 EUR |
| Annual cost | 600 - 2,400 EUR | 1,800 - 4,000 EUR (maintenance) |
| Branded experience | No | Yes |
| Structured DMS | Limited | Full |
| E-signature | Paid option | Native |
| Unified SSO | Rare | Yes |
| Time to launch | 1 - 3 weeks | 10 - 16 weeks |
| Hardened hosting option | No | Yes |
Mini case study
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Mark, partner at a 9-person firm in London, manages 210 clients. Document collection ran over email: 8 hours a week of chasing spread across the team, roughly 350 hours a year. At a loaded cost of 45 EUR/hour, that is 15,750 EUR of unproductive time annually. With a custom portal at 32,000 EUR, he targets a 60% cut in chasing, saving about 9,450 EUR a year. Payback in just over three years excluding brand and satisfaction gains, faster once recovered time is rebilled in production.
FAQ
Is a custom portal justified below 50 clients? Rarely. Under 30-50 active clients the bundled module covers the basics. Custom pays off above that, when chasing exceeds 5 hours a week.
How long to launch? Expect 10 to 16 weeks in 2026, discovery included. A working MVP (upload, DMS, notifications) can ship in 8 weeks, with e-signature and SSO in a second batch.
Is the e-signature legally valid? Yes, with an eIDAS integration (advanced or qualified via Yousign, Docusign or equivalent). Budget 2,500 to 6,000 EUR of build plus per-signature fees.
Do we need specialist secure hosting? Not for a standard accounting firm. A GDPR-compliant European host with encryption is enough; order of magnitude 1,200 to 3,000 EUR/year.
Can the portal connect to our production tool? Yes if the vendor exposes an API. Budget 3,000 to 8,000 EUR for integration. Without an API, automated import/export still works but less smoothly.
Let's scope your project. Tell us your client volume, current production software and signing needs: we price a right-sized portal, between 18,000 and 45,000 EUR. 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.
