The verdict in three sentences
Vertical SaaS wins when it covers more than 80 % of your need: live in weeks, predictable cost, a vendor that pools your sector's evolutions. Custom wins when your differentiation lives in the 20 % the SaaS does not cover: zero process compromise, no lock-in, your data. The 2026 rule: measure the real coverage rate BEFORE signing, not the sales demo.
The decision grid: 6 criteria, 2 columns
Before comparing prices, compare fit. A vertical SaaS at 90 % coverage often beats custom; at 60 % it forces you to bend your processes.
| Criterion | Vertical SaaS | Custom |
|---|---|---|
| Functional coverage | 60 - 90 % standard | 100 % targeted |
| Cost per user / year | 240 - 720 EUR | 0 EUR |
| Rollout | 4 - 10 weeks | 12 - 24 weeks |
| Lock-in | medium to strong | none |
| Exports / reversibility | variable (paid API) | total |
| Sector evolutions | included | on you |
The most underrated criterion is reversibility: can you recover 100 % of your data in a usable format if you leave? Many vertical SaaS charge for the export API or limit it.
5-year TCO: the effect of user count
Cost per user is linear on the SaaS side and nil on the custom side after the build. 2026 order of magnitude for 25 users:
| Item (25 users, 5 yrs) | Vertical SaaS | Custom |
|---|---|---|
| Build / onboarding | 12,000 EUR | 70,000 EUR |
| Subscription / licences | 25 x 480 x 5 = 60,000 EUR | 0 EUR |
| Maintenance | included | 14 % x 70,000 x 5 = 49,000 EUR |
| Hosting | included | 1,800 x 5 = 9,000 EUR |
| Total 5-year cost | 72,000 EUR | 128,000 EUR |
| At 50 users (5 yrs) | 132,000 EUR | ~128,000 EUR |
At 25 users vertical SaaS is clearly cheaper; the crossover happens around 45 to 55 users, after which custom becomes competitive while remaining an owned asset.
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Mini case study
Lotte, operations director of an 18-clinic veterinary network in Amsterdam, evaluates a veterinary SaaS at 520 EUR/user/year for 40 users. Coverage: 85 %, but her post-op follow-up protocol (her commercial differentiation) does not fit the standard. The SaaS costs her 40 x 520 x 5 + 15,000 EUR onboarding = 119,000 EUR over 5 years, never covering her protocol. A targeted build at 85,000 EUR + 59,500 EUR maintenance = 144,500 EUR, but embeds her protocol and removes lock-in risk. She picks custom because the missing 15 % is precisely her competitive edge.
FAQ
How do I measure the real coverage rate? List your 30 to 50 priority use cases and tick those the SaaS covers out of the box (no development). Below 75 %, custom is worth a serious look again.
Is vertical SaaS always faster? Yes for go-live (4-10 weeks versus 12-24), but integration with your existing tools and data migration can add several weeks.
What is lock-in concretely? It is the difficulty and cost of leaving: proprietary formats, paid export API, long migration. Strong lock-in can cost 10,000 to 30,000 EUR the day you switch.
Can you start on SaaS then move to custom? Yes, it's a prudent strategy: validate the need on SaaS for 18-24 months, then build when user volume justifies the investment and the need has stabilised.
Who owns the data in each case? With custom, you do, unconditionally. With SaaS, you do in theory, but access and export depend on the contract: check the reversibility clause before signing.
Let's scope your project. Send us your 30 priority use cases and your user count: we compute your SaaS coverage rate and the tipping point toward custom. Detailed quote within 48h. 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.
