The verdict in three sentences
Buying an off-the-shelf SaaS wins when your process is standard and your headcount modest; building custom wins when the process is specific or per-user licences get heavy. The economic tipping point often sits between 20 and 30 active users. The real question is not the entry price but the 5-year TCO and how well the tool fits your business.
5-year TCO: SaaS vs custom
A SaaS looks cheaper up front, but cumulative subscription cost grows with the team. Let us compare for a company of 25 users at 45 EUR/user/month (2026 order of magnitude).
| Item | Market SaaS | Custom build |
|---|---|---|
| Upfront cost | 0 - 5,000 EUR (setup) | 40,000 - 120,000 EUR (build) |
| Annual recurring | 13,500 EUR (25 x 45 x 12) | 15 to 20% of build |
| 5-year cost (25 users) | ~70,000 - 75,000 EUR | ~75,000 - 155,000 EUR |
| 5-year cost (60 users) | ~165,000 EUR | build unchanged + maint. |
| Business fit | 60 to 85% | 95 to 100% |
| Code ownership | no | yes |
At 25 users SaaS stays competitive; at 60 users, custom often becomes cheaper over 5 years while fitting the process perfectly.
Decision grid by specificity
The deciding factor is not budget but how specific your process is and how much vendor dependence you can accept.
| Criterion | Favor buying | Favor building |
|---|---|---|
| Process specificity | standard (accounting, CRM) | niche / proprietary rules |
| Number of users | < 20 | > 30 |
| Usage horizon | < 3 years | > 4 years |
| Integration needs | 1 or 2 standard | multiple / custom |
| Vendor dependence | acceptable | avoid (critical data) |
| Competitive edge | non-differentiating | core differentiation |
A hybrid approach also exists: buy for standard functions (payroll, accounting) and build custom for the differentiating part.
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Mini case study
Thomas, IT director of a mid-sized logistics firm in Amsterdam (55 users of a future planning tool), compares a SaaS at 48 EUR/user/month, i.e. 31,680 EUR/year, to a custom build at 95,000 EUR with 16,000 EUR of annual maintenance. Over 5 years: the SaaS costs ~158,000 EUR, custom ~159,000 EUR for a business fit rising from 70% to 98% and no vendor lock-in. The decision leans toward building because the slotting process is a competitive edge no SaaS covers.
FAQ
From how many users is custom worthwhile? Often beyond 25 to 30 users, but it depends on the per-licence price: always compute the 5-year TCO rather than the entry price.
Isn't SaaS safer long term? Not necessarily: price increases, changing terms and discontinued features are real vendor-dependence risks.
Can we migrate from SaaS to custom later? Yes, provided you can export your data; budget 10 to 20% of the build for data migration.
Is custom slower to deploy? Yes, 4 to 9 months versus a few weeks for SaaS; it is a time-to-market vs business-fit trade-off.
How do we limit build risk? Split into phases and validate each module in production before committing the next.
Let's scope your project. Share your user count, your process specificity and your current tools, and we will build your build-vs-buy TCO comparison. 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.
