The verdict in three sentences
If your business process matches 80% of the standard (purchasing, sales, stock, accounting), Odoo or a vertical ERP is almost always the sound economic choice. As soon as your competitive edge relies on a specific process the vendor will not follow, custom software avoids costly customization and the vendor lock-in that traps you at every version upgrade. The decisive variable is the exit cost, not the entry price.
The real 5-year cost
Odoo shows a modest subscription, but integration and specific modules weigh heavily. 2026 order of magnitude, France, 25-user SME.
| Item | Odoo / vertical ERP | Custom |
|---|---|---|
| License / subscription | 25-45 EUR/user/month | 0 (ownership) |
| Initial integration | 15,000-60,000 EUR | Included in build |
| Initial development | — | 50,000-150,000 EUR |
| Module customization | 8,000-40,000 EUR | Included |
| Annual maintenance | 12-18% of build | 15-20% of build |
| Exit / migration cost | High (lock-in) | Moderate (you own the code) |
| Version upgrade | May break custom | Controlled |
For 25 users at 35 EUR/month: 10,500 EUR/year subscription, i.e. 52,500 EUR over 5 years, before integration. Add 40,000 EUR of integration: 92,500 EUR — close to a mid-range custom build, but without code ownership.
When to choose what
| Situation | Odoo / ERP | Custom |
|---|---|---|
| Standard market processes | Ideal | Oversized |
| Need to start in < 3 months | Fast | Slower |
| Differentiating business process | Costly custom | Ideal |
| Tight initial budget | Spread (subscription) | Heavy upfront |
| Fear of vendor lock-in | Real risk | You own it |
| Multiple integrations (5+) | Existing connectors | To be built |
| Strong functional evolution | Limited by vendor | Total |
Mini case study
Claire, CFO of a Lyon trading SME (30 users), compares Odoo to custom. Odoo: subscription 30 × 35 EUR = 1,050 EUR/month, i.e. 12,600 EUR/year, plus 45,000 EUR of integration and 22,000 EUR of specific modules = 67,000 EUR in year one, then 12,600 EUR/year. Over 5 years: 117,400 EUR. Custom is quoted at 95,000 EUR plus 16,000 EUR/year of maintenance = 159,000 EUR over 5 years but with code ownership and zero lock-in risk. Claire picks Odoo: her process is 85% standard, the 41,600 EUR five-year gap is not justified. She reserves custom only for the dynamic pricing module, which is genuinely differentiating.
FAQ
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Is Odoo really cheaper than custom?
Short term yes, long term it depends on customization. Every custom module on Odoo must be retested at each version upgrade, inflating maintenance by 15-30% versus an unmodified standard.
What is vendor lock-in in practice?
It is the risk of price hikes, license changes (Odoo tightened its terms several times) and the obligation to follow versions. Plan a reversibility clause and a documented data export.
Is custom riskier to deliver?
Yes on timeline and initial quality, but less on longevity. Secure it with short sprints, continuous acceptance testing and a code repository you own.
Can you combine Odoo and custom?
Yes, it is common: Odoo for standard accounting and stock, an API-connected custom module for the differentiating process. You confine costly custom to the strict minimum.
What amortization horizon should I use?
Reason over 5 years minimum. Below 3 years, the SaaS/ERP subscription almost always wins; beyond 5 years, custom code ownership becomes an asset.
Let's scope your project. Send us your process map and user count: we will cost the Odoo vs custom gap over 5 years, full 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.
