The verdict in three sentences
In Dublin in 2026, a vertical extranet SaaS costs 20-100 EUR/seat/month and a custom extranet 50 000-110 000 EUR + run, which shifts the real question to user count and length of use. Below ~40 users over 3 years, SaaS is almost always cheaper; above that, custom becomes competitive and makes you the owner. The deciding factor is not just price: it is vendor lock-in and the ability to customise your business processes.
3-year TCO by user count
Assumption: SaaS at 60 EUR/seat/month, custom at 80 000 EUR build + 800 EUR/month run (i.e. 108 800 EUR over 3 years).
| Users | SaaS 3 yrs (EUR) | Custom 3 yrs (EUR) | Cheaper |
|---|---|---|---|
| 10 | 21 600 | 108 800 | SaaS |
| 25 | 54 000 | 108 800 | SaaS |
| 40 | 86 400 | 108 800 | SaaS |
| 60 | 129 600 | 108 800 | Custom |
| 100 | 216 000 | 108 800 | Custom |
| 200 | 432 000 | 108 800 | Custom |
The crossover sits around 50-55 users under these assumptions. If your SaaS bills per module or per transaction, the threshold often drops toward 40 users.
Beyond price: the criteria that really decide
| Criterion | Market SaaS | Custom |
|---|---|---|
| Entry cost | Low, monthly | High, capitalised |
| Business customisation | Limited to options | Total |
| Vendor lock-in | Strong (data, API) | You own it |
| Time to launch | 2-6 weeks | 4-8 months |
| Pricing scalability | Per seat/module | Low marginal cost |
| Data reversibility | Often constrained | Full control |
| Dependence on vendor roadmap | Yes | No |
SaaS saves time upfront but ties you to its roadmap and price increases. Custom demands an initial investment but removes lock-in and absorbs growth with no per-seat cost.
Mini case study
Karim, operations director of a construction-supply wholesaler in Dublin, equips 70 sales reps and pro customers with an ordering and tracking extranet. The chosen SaaS bills 65 EUR/seat/month, i.e. 54 600 EUR/year and 163 800 EUR over 3 years.
A custom extranet is quoted at 85 000 EUR + 850 EUR/month run, i.e. 115 600 EUR over 3 years. Estimated saving: ~48 200 EUR over 3 years, plus code ownership and the end of per-seat cost. Since his client-specific pricing rules are too particular for the SaaS, he chooses custom: the switch is financially and strategically justified from the first full year of use.
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FAQ
At how many users does custom pay off?
Under typical 2026 assumptions, the threshold is 40-60 users over 3 years. Above that, SaaS per-seat cost eventually exceeds an amortised build.
Is vendor lock-in really that important?
Yes: extracting your data and migrating off a SaaS can cost several months and export fees. With custom, you keep ownership of the code and database.
Isn't SaaS safer and better maintained?
A good SaaS includes security and updates, a real advantage for small teams. But a well-built custom extranet with maintenance reaches the same level and follows your business rules.
Can we start on SaaS then move to custom?
Yes, a common strategy: validate usage on SaaS, then internalise once user count and specific needs justify the build.
How much is the run of a custom extranet?
Budget 400-1 200 EUR/month (EU hosting, monitoring, backups, patches), added to build cost for an honest TCO.
Let's scope your project. Tell us your user count, specific processes and the SaaS you are comparing: we will calculate your 3-year TCO. 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.
