The verdict in three sentences
A vertical licensed tool (EUR 40-90/user/month) is unbeatable to start fast, but it caps your productivity the moment your engagements step outside the standard box. Custom development (EUR 40,000-110,000) pays off beyond 10-12 staff, once the 8 to 12 hours saved each week on re-keying and engagement tracking outweigh the write-off. The real question is not the purchase price but the cost of the friction you absorb every day.
Licence or custom : the real comparison
Vertical vendors cover 80 % of a firm's needs. The remaining 20 % — your own processes, your document store, your client reporting — are precisely what differentiate you and cost the most in lost time.
| Criterion | Vertical licence | Custom |
|---|---|---|
| Upfront cost | EUR 0-3,000 (setup) | EUR 40,000-110,000 |
| Recurring cost | EUR 40-90/user/month | Maintenance EUR 600-1,400/month |
| Time to launch | 2 to 6 weeks | 4 to 7 months |
| Process fit | Low to medium | Total |
| Accounting-production integration | Often limited | Native (API) |
| Code ownership | No | Yes |
For a 12-person firm, the licence runs about EUR 540-1,080/month, i.e. EUR 6,500-13,000/year of recurring, non-capitalised spend. Over 5 years that often exceeds an amortised custom build.
What custom actually changes
A tool tailored to your firm unites what is scattered today across spreadsheets, email and production software:
| Module | Measured gain | Annual impact (12-person firm) |
|---|---|---|
| Engagement & deadline tracking | -30 % late filings | ~120 h recovered |
| Indexed store + full-text search | -50 % document search time | ~200 h recovered |
| Secure client portal | -40 % chasing emails | ~90 h recovered |
| Real-time reporting | Faster decisions | Margin +2 to 4 pts |
The 4-7 month timeline splits into scoping (3-5 weeks), iterative build (3-5 months) and data migration. Maintenance (EUR 600-1,400/month) covers fixes, regulatory changes and hosting.
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Mini case study
Claire, partner at an accounting firm in London (12 staff, EUR 4.2M in fees). Each staffer loses on average 9 h/week to re-keying and document search. At a loaded cost of EUR 45/h, that is 12 × 9 × 45 = EUR 4,860/week, roughly EUR 220,000/year of non-billable time.
A custom tool at EUR 78,000 plus maintenance of EUR 1,000/month (EUR 12,000/year) cuts that waste by 60 %. Annual saving: ~EUR 132,000. Payback in 8 to 9 months, before any margin gains on better-run engagements.
FAQ
What does custom accounting-firm software really cost in 2026 ? Expect EUR 40,000-110,000 depending on scope (document store, portal, production integration). A first useful module often ships around EUR 40,000-55,000.
How long until it is live ? Between 4 and 7 months. An MVP focused on engagement tracking can ship in 10-14 weeks, then grow in batches.
Can it integrate with my accounting-production software ? Yes, via API or automated imports/exports. That is exactly the advantage of custom over closed licences.
What maintenance budget should I plan ? Maintenance of EUR 600-1,400/month covers fixes, regulatory updates and hosting — the 2026 ballpark for a mid-sized firm.
At what size does custom pay off ? Usually beyond 10-12 staff, when licences plus lost time exceed the project's 3-5 year write-off.
Let's scope your project. Tell us your firm size, current production software and priority modules and we will price a scope between EUR 40,000 and 110,000. 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.
