The verdict in three sentences
A custom client portal for a London accounting firm ranges from 18,000 to 52,000 GBP in 2026, versus 25 to 100 GBP per user per month for a generic SaaS module. Custom becomes worthwhile once you handle more than 150 client files and email exchange saturates your inboxes. The real return isn't the price but the 5 to 10 weekly hours each staff member recovers on document collection.
How much a client portal costs in 2026
Budget depends mostly on the number of integrations (production software, e-signature, document management) and interface customisation. Here are 2026 market benchmarks.
| Scope | Included features | 2026 price (GBP) | Timeline |
|---|---|---|---|
| Essential | Secure upload, notifications, per-client space | 18,000 - 26,000 | 10-12 weeks |
| Intermediate | + e-signature, auto reminders, document store | 27,000 - 39,000 | 12-14 weeks |
| Advanced | + production software integration, dashboard | 40,000 - 52,000 | 14-16 weeks |
| Maintenance | Hosting, updates, support | 300 - 700 /month | recurring |
UK/EU hosting (GDPR) adds 50 to 140 GBP per month depending on stored document volume.
Custom vs SaaS module: the right call
A SaaS module starts fast but charges per user and limits customisation. Custom costs more upfront but pays off at scale.
| Criterion | SaaS module | Custom portal |
|---|---|---|
| Entry cost | 0 - 3,500 GBP | 18,000 - 52,000 GBP |
| Recurring cost (30 users) | 750 - 3,000 GBP/month | 300 - 700 GBP/month |
| Brand customisation | Low | Total |
| Production software integration | Vendor-limited | Bespoke |
| E-signature | Often paid add-on | Included |
| Data ownership | Vendor | Firm |
Over 3 years, a 25-staff firm often pays more in SaaS subscriptions than in amortised custom development.
Mini case study
Claire, managing partner of a 22-staff accounting firm in London, handles 380 files. Each staff member spends about 6 hours per week chasing and filing documents by email. At a loaded cost of 40 GBP/hour, that is 22 × 6 × 40 = 5,280 GBP per week, nearly 253,000 GBP per year of unproductive time.
With a 38,000 GBP custom portal cutting that time by 40 %, the firm saves roughly 101,000 GBP per year. The investment pays back in under 4 months, hosting included.
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FAQ
How long to deliver an accounting client portal?
Expect 10 to 16 weeks in 2026 depending on integrations. An essential scope without production-software connection ships in 10 to 12 weeks.
Is e-signature compliant?
Yes, using an eIDAS-equivalent provider (simple or advanced level). Budget 0.50 to 2 GBP per signature or a monthly plan by volume.
Can the portal connect to our production software?
Yes, via API or dedicated connector. That pushes the budget toward the upper tier (40,000-52,000 GBP) but removes double entry.
Where is client data hosted?
In the UK or EU on GDPR-compliant infrastructure. For an accounting firm, specialised health hosting isn't required.
What real time savings should we expect?
Between 5 and 10 hours per week per staff member on collecting, filing and chasing documents, depending on portfolio size.
Let's scope your project. Tell us your file volume, your production software and your priorities (signature, document store, reminders) for an indicative budget of 18,000 to 52,000 GBP. 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.
