The verdict in three sentences
In 2026, the buy (vertical SaaS) or build (custom platform) decision isn't settled by gut feel but by 5-year TCO and fit with your process. A vertical SaaS at EUR 30-150/user/month is unbeatable at low headcount; beyond 40-60 users, custom at EUR 40,000-120,000 + 15-20 %/year maintenance often becomes cheaper — and you own it. The hidden decider is vendor lock-in: price hikes, imposed features, data that's hard to extract.
The 5-year TCO calculation
Vertical SaaS costs grow linearly with headcount; custom has a heavy upfront cost then stable maintenance. The crossover depends mostly on user count.
| Scenario (60 users) | Vertical SaaS (EUR 80/user/mo) | Custom (EUR 80,000 + 18 %/yr) |
|---|---|---|
| Year 1 | 57,600 EUR | 80,000 EUR |
| Year 2 | 115,200 EUR | 94,400 EUR |
| Year 3 | 172,800 EUR | 108,800 EUR |
| Year 4 | 230,400 EUR | 123,200 EUR |
| Year 5 | 288,000 EUR | 137,600 EUR |
| 5-year TCO | 288,000 EUR | 137,600 EUR |
At 60 users, the crossover hits as early as year 2. Conversely, with 10 users vertical SaaS stays the most rational (EUR 48,000 over 5 years vs EUR 137,600).
Buy vs Build: the decision grid
Price is only one criterion. Process fit, time-to-value and data control weigh just as much for a mid-market firm.
| Criterion | Vertical SaaS (buy) | Custom (build) |
|---|---|---|
| Time to start | 2 – 6 weeks | 4 – 7 months |
| Upfront cost | Low (subscription) | EUR 40,000 – 120,000 |
| Recurring cost | EUR 30 – 150/user/mo | 15 – 20 %/yr maintenance |
| Process fit | Medium (you adapt) | Total (it adapts to you) |
| Data ownership | Vendor | You |
| Lock-in risk | High | None |
| Roadmap | Vendor's roadmap | Your roadmap |
Practical rule: buy to start fast and under 30-40 users, build when the process is a competitive edge or headcount passes the crossover. A hybrid also works: vertical SaaS + custom connectors to fill the gaps.
Mini case study
Marianne, CIO of a 140-person industrial mid-market firm in Berlin, ran a vertical production-management SaaS at EUR 95/user/month for 55 seats, i.e. EUR 62,700/year. Annual hikes (+9 %) and two paid add-on modules pushed her to model a custom platform: EUR 92,000 build + EUR 16,560/year maintenance. Over 5 years: EUR 174,560 custom vs EUR 342,000 projected in SaaS (with inflation). A EUR 167,000 saving, and the end of depending on a vendor imposing its roadmap.
Need a professional website?
Kolonell builds websites that attract clients, optimized for the Sénégalese market. Free quote in 2 minutes.
FAQ
Above how many users does custom pay off?
As a 2026 order of magnitude, the threshold sits between 40 and 60 users for a SaaS at EUR 80-100/user/month. Below, vertical SaaS stays cheaper; above, custom wins over 5 years.
What is vendor lock-in, concretely?
It's your dependence on a vendor's prices, features and calendar. In practice: 8-12 %/year hikes, paid add-on modules, and data export that's sometimes charged or limited.
Is custom expensive to maintain?
Count 15 to 20 % of build cost per year. On an EUR 80,000 platform that's EUR 12,000 to 16,000/year, often below the cumulative subscriptions of a SaaS at high headcount.
Can you combine the two?
Yes. A hybrid keeps a vertical SaaS for standard functions and grafts custom connectors for your specifics. It's often the best cost/speed compromise.
How long to deliver a custom platform?
Between 4 and 7 months depending on scope, versus 2 to 6 weeks to deploy a vertical SaaS. Custom requires serious scoping before any development.
Let's scope your project. Give us your user count, current SaaS and its cost, and we'll model the 5-year buy vs build TCO and the crossover point. 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.
