The verdict in three sentences
Vertical legal tech wins on speed and low upfront cost, but imposes its workflows and charges per seat. Custom costs more up front (EUR 45,000-90,000) but removes the per-seat cost, freely integrates filing/accounting/DMS and belongs to you. The financial break-even sits around 16-18 users, or the moment a strategic workflow does not fit the SaaS.
Head-to-head of the two models
| Criterion | Vertical legal tech | Custom build |
|---|---|---|
| Upfront cost | EUR 0 - 5,000 (config) | EUR 45,000 - 90,000 |
| Per-seat cost | EUR 70 - 130 /user/month | EUR 0 |
| Rollout time | 3 - 6 weeks | 4 - 6 months |
| Workflows | vendor-imposed | 100% tailored to the firm |
| Filing/accounting/DMS integrations | limited / paid | free |
| Reversibility (data exit) | varies, check the contract | total, you own it |
| Roadmap | vendor-driven | driven by you |
The quantified break-even
At EUR 100/user/month, SaaS costs EUR 1,200/year per lawyer. Here is the 3-year cost by firm size, against a median custom build at EUR 65,000 + 18%/yr maintenance (~EUR 35,000 over 3 years, total ~EUR 100,000).
| Lawyers | SaaS 3-yr (EUR 100/user) | Custom 3-yr | Advantage |
|---|---|---|---|
| 5 | EUR 18,000 | ~EUR 100,000 | SaaS |
| 10 | EUR 36,000 | ~EUR 100,000 | SaaS |
| 16 | EUR 57,600 | ~EUR 100,000 | SaaS (edge) |
| 25 | EUR 90,000 | ~EUR 100,000 | balanced |
| 40 | EUR 144,000 | ~EUR 100,000 | Custom |
On pure cost, custom becomes worthwhile beyond ~28-30 lawyers over 3 years. But the decision is not only price: a blocked strategic workflow, a deep-integration need or a total-reversibility requirement can justify custom well before that threshold.
Mini case study
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Julia, partner at a scaling firm in Berlin (12 lawyers, targeting 30 in 3 years), was undecided. At 12 lawyers today, SaaS costs EUR 43,200 over 3 years — cheaper. But her projection to 30 lawyers would push SaaS past EUR 108,000/3 years, above custom. Above all, her need for a bespoke document-approval workflow and a specific accounting integration did not fit the SaaS. She chose a custom build at EUR 68,000: worthwhile once the firm passes ~19 lawyers, and aligned with her growth roadmap. Reversibility — owning her data and code — was the deciding factor.
FAQ
At how many lawyers does custom pay off? On pure 3-year cost, around 28-30 lawyers at EUR 100/user/month. But a blocking business need can justify it far earlier, from 12-15 lawyers.
Is vertical SaaS really faster? Yes: 3-6 weeks versus 4-6 months. If the need is urgent and standard, SaaS gets the firm live immediately, with migration possible later.
How much is reversibility worth? A lot. Always check the SaaS data-export clause in the contract. With custom you own the code and data, with no dependence on a vendor's roadmap.
Can we start on SaaS then move to custom? Yes, a common trajectory: validate real needs on SaaS for 12-24 months, then build custom once the firm is stable and growing.
What maintenance budget for custom? About 18%/yr of the development base, i.e. ~EUR 11,700/year for a EUR 65,000 project. It covers security, fixes and features.
Let's scope your project. Give us your current and 3-year headcount, critical workflows and integrations: we will produce the quantified SaaS-vs-custom decision grid. 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.
