Legal Software: SaaS Licence vs Custom Build — 5-Year TCO in 2026

The verdict in three sentences

Below 15 users, a SaaS licence is unbeatable on upfront cost and time to launch. Beyond 20 seats over a 5-year horizon, a custom build becomes competitive because it removes the per-seat cost and makes you the owner of the code. The real question isn't the sticker price but reversibility, e-filing/accounting integration and the lock-in you accept.

Legal SaaS: what you actually rent

Market suites (Secib Néo, Jarvis Legal, Kleos) bill per user per month, with add-on modules and recurring price increases. Here is a 2026 order of magnitude for a Bordeaux firm of 15 staff.

With average price inflation of 5%/year, the bill climbs mechanically. Over 5 years, the base licence alone (no modules) is around 40,500 EUR, and the full package exceeds 65,000 EUR.

Custom build: what you buy

Custom software is paid at build time, then via ongoing maintenance. You own the code, and cost no longer depends on seat count.

The break-even point

The crossover sits around 35-40 users over 5 years, earlier (year 4) if you add several modules and integrate accounting heavily. Below that, SaaS wins; above it, custom prevails, especially when reversibility matters (full export, EU hosting, no vendor dependency).

Mini case study

Mr Lambert, managing partner of a 15-strong firm in Bordeaux, plans to reach 24 seats within 3 years. On full SaaS, his bill would rise from about 12,000 EUR to over 20,000 EUR/year with growth and +5%/year, i.e. ~85,000 EUR cumulative over 5 years. On custom, he pays 85,000 EUR at build then 14,000 EUR/year, i.e. 155,000 EUR over 5 years — but in year 6 he pays only maintenance (14,000 EUR) while SaaS would already cost 22,000 EUR. Beyond the 5-year horizon, with his growth, custom saves ~8,000 EUR/year while eliminating lock-in risk.

FAQ

What does legal SaaS really cost in 2026? Budget 45 EUR/user/month for the base, plus 15-40% in modules (accounting, DMS, e-filing). For 15 seats, the full package is around 12,000 EUR/year, before ~5%/year hikes.

When does custom become worthwhile? Beyond 20-25 users over 5 years. The crossover is around 35-40 seats, sooner if you integrate accounting and e-filing heavily.

Does GDPR require EU hosting? You must ensure compliant, secure processing; EU hosting greatly simplifies compliance and reassures clients. A custom build lets you pick a certified ISO 27001 EU host.

What is reversibility and why is it critical? It's your ability to recover 100% of your data in a usable format if you leave the vendor. In SaaS it's often limited; in custom you own the database and code.

What maintenance budget for custom? Maintenance of 14-16% of the build per year, about 14,000 EUR/year for an 85,000 EUR project, covering updates, security and support.

Let's scope your project. Tell us your headcount, integrations (e-filing, accounting) and indicative budget: we'll model the SaaS vs custom break-even for your firm. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.