The verdict in three sentences
Migrating from a vertical SaaS to custom is more than a build: it is a data migration, a parallel-running period and training to orchestrate without halting operations. The realistic 2026 total runs €46,000 to €120,000, over a 12- to 24-week timeline. The investment repays through the removed subscription in 18 to 36 months, after which the tool becomes a net asset.
Migration phases costed
| Phase (2026 order of magnitude) | Timeline | Cost |
|---|---|---|
| Audit + reverse-engineering the SaaS | 2–3 wks | €6,000–20,000 |
| Build of the replacement tool | 8–14 wks | €40,000–100,000 |
| Data extraction and migration | 2–4 wks | included/€6,000–20,000 |
| Parallel running | 2–4 months | €1,500–6,000 (dual sub) |
| User training | 1–2 wks | €2,000–8,000 |
| Post-migration support | recurring | €450–1,200/month |
Reverse-engineering is the underestimated step: documenting what the SaaS truly does (hidden business rules, edge cases) avoids reproducing functional gaps in the new tool.
TCO before / after over 5 years
Assumption: current SaaS €1,600/month, 12 %/year increase. One-off migration €75,000, support €800/month, hosting €120/month.
| Year | SaaS kept (cumulative) | Custom migrated (cumulative) |
|---|---|---|
| 0 | €0 | €75,000 |
| 1 | €19,200 | €75,000 + €11,040 = €86,040 |
| 2 | €40,704 | €97,080 |
| 3 | €64,792 | €108,120 |
| 4 | €91,771 | €119,160 |
| 5 | €121,758 | €130,200 |
Breakeven lands between year 4 and year 5 in this cautious scenario; it drops to 30 months if your subscription exceeds €2,500/month or rises 15 %/year. Beyond that, each year you save the gap between the (rising) subscription and the (flat) support fee.
Switching over without breakage
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- Phased migration: move a non-critical module first, validate, then extend.
- Parallel running: keep the SaaS read-only for 2 to 4 months to secure history.
- Data reversibility: demand a full dated export before cancelling.
- Targeted training: €2,000–8,000 to avoid the early-weeks productivity drop.
Mini case study
Stefan runs a 32-person logistics SME in Berlin, paying €1,700/month for a vertical SaaS whose limits block his growth (no API, frozen reporting). Migration costing: audit €12,000, build €68,000, data migration €9,000, 3-month parallel €4,500, training €5,000, i.e. €98,500 total, plus €800/month support. His subscription, at 12 %/year, would cost €130,000 over 5 years. The migration pays back in 28 months and, from year 3, he saves the gap while running a tool that finally scales with his growth and a code he owns.
FAQ
What is the total cost of a SaaS-to-custom migration? In 2026, budget €46,000 to €120,000 all-in (audit, build, migration, parallel, training), plus €450–1,200/month support.
How long to migrate without interrupting operations? 12 to 24 weeks, including 2 to 4 months of parallel running to secure the switch and data history.
How fast does the investment pay back? Usually 18 to 36 months depending on the removed subscription; the higher and faster-rising the subscription, the quicker the return.
Is data migration risky? It is the most sensitive step: it requires a full export, cleanup and rigorous mapping. Parallel running for 2 to 4 months secures history before cancellation.
Can I migrate in stages? Yes, and it is recommended: move a non-critical module first, validate in real conditions, then extend, limiting operational risk.
Let's scope your project. Send us your current SaaS, its monthly cost and your blocking limits: we price the migration phase by phase (from €46,000) and the breakeven against your subscription. 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.
