The verdict in three sentences
For fewer than 15-20 users and standard needs, a SaaS client portal at 25-70 GBP/user/month stays the most rational. Beyond 30 users, or when customisation and data ownership become critical, custom (40,000-80,000 GBP upfront + maintenance) breaks even in 24 to 36 months. The real trade-off is not only financial: it is control of your processes and your data protection compliance.
Total cost over 3 years
Comparing a subscription to an investment means reasoning in total cost of ownership (TCO) over the tool's life, here 3 years, for 30 users.
| Scenario | Year 1 cost | 3-year cost | Note |
|---|---|---|---|
| SaaS 25 GBP/user/month | 9,000 GBP | 27,000 GBP | 30 users, entry level |
| SaaS 45 GBP/user/month | 16,200 GBP | 48,600 GBP | Advanced features |
| SaaS 70 GBP/user/month | 25,200 GBP | 75,600 GBP | Premium + support |
| Custom standard | 52,000 GBP* | 70,800 GBP | *40,000 build + 1,050/mo |
| Custom full | 80,000 GBP* | 98,800 GBP | *SSO, ERP, multi-entity |
*Custom year 1 = build + 12 months maintenance (900-1,500 GBP/month). Amounts are a 2026 order of magnitude.
At 45 GBP/user/month, SaaS exceeds custom-standard cost beyond 3 years; at 25 GBP/user/month, SaaS stays cheaper over 3 years but you own nothing.
Beyond price: the decision criteria
TCO is not the whole story. Here are the criteria that often tip the balance for a London IT director.
| Criterion | SaaS | Custom |
|---|---|---|
| Time to launch | Days | 8-22 weeks |
| Customisation | Limited to options | Total |
| Data ownership | With the vendor | With you |
| Marginal cost per user | High (linear) | Near zero |
| Vendor lock-in | High (price hikes, shutdown) | Low |
| Data protection / EU hosting | Varies by vendor | Controlled |
| Deep ERP integration | Often constrained | Bespoke |
Need a professional website?
Kolonell builds websites that attract clients, optimized for the Sénégalese market. Free quote in 2 minutes.
The more your user count grows, the more SaaS's linear cost works against you and the more custom, with near-zero marginal cost, pays off.
Mini case study
Nadia, IT director of a London services group (45 active users), pays a SaaS at 55 GBP/user/month, i.e. 29,700 GBP/year. Over 3 years that is 89,100 GBP, with no control over data or product roadmap. A full custom portal is quoted at 80,000 GBP + 1,300 GBP/month maintenance, i.e. 96,800 GBP over 3 years. The 3-year gap is 7,700 GBP in the SaaS's favour, but from year 4 custom costs only 15,600 GBP/year (maintenance) versus 29,700 GBP for SaaS: a 14,100 GBP/year saving. Over a 5-year horizon custom wins clearly, while securing data protection compliance.
FAQ
Above how many users does custom win? As a rule, beyond 30 users on a SaaS at 50 GBP/month, custom becomes competitive over 3-4 years and very advantageous beyond.
Is SaaS really faster? Yes to start (a few days), but customisation and integration with your systems can take as long as a targeted custom build.
Who owns the data in SaaS? The vendor hosts your data under its terms. If prices rise or the service shuts down, reversibility is often complex and costly.
Can we start on SaaS then move to custom? Yes, it is a common strategy: validate the need on SaaS for 12-18 months, then internalise via a custom portal when volumes justify it.
Does data protection favour custom? Custom with EU/UK hosting gives total control of processing, useful for sensitive sectors. Some SaaS tools are compliant, others host outside the region: check the contract.
Let's scope your project. Give us your user count, your current SaaS and its price: we'll model your 3-year TCO and price the custom alternative. 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.
