The verdict in three sentences
A custom vertical platform that unifies your processes costs 60,000 to 180,000 EUR over 16 to 32 weeks, depending on the number of modules and integrations. The real success factor isn't budget but the quality of the scoping document: fuzzy scoping blows up costs in change requests. Phase into deliverable batches so the value from the first funds the next.
The structure of a scoping document that holds
A scoping document isn't a feature list: it's a document that aligns business, technical and budget. Here's the expected structure and each part's weight in project success.
| Scoping section | Expected content | Weight on success |
|---|---|---|
| Context & business goals | Current pains, target KPIs | Very high |
| Process mapping | Flows, roles, edge cases | Very high |
| Functional scope per module | Prioritized user stories (MoSCoW) | High |
| Integrations & data migration | ERP, accounting, third-party APIs, volume | High |
| Non-functional requirements | Perf, security, GDPR, availability | Medium |
| Constraints & out-of-scope | What the project will NOT do | High |
| Phasing & acceptance criteria | Batches, milestones, definition of done | Medium |
The "out-of-scope" section is the one people forget and the one that prevents the most change requests: it protects budget as much as timeline.
Custom build vs SaaS assembly: the comparison
Before building, the honest question is: can you assemble existing SaaS? Sometimes yes. But once your process is your competitive edge, assembly shows its limits.
| Criterion | SaaS assembly | Custom platform |
|---|---|---|
| Initial cost | 5,000-20,000 EUR (setup) | 60,000-180,000 EUR |
| Subscriptions/yr (5 tools) | 12,000-40,000 EUR | 3,000-10,000 EUR (infra) |
| Fit to business process | Limited (you adapt to the tool) | Total |
| Integration/glue cost | High and recurring | Included, native |
| Data ownership | Scattered | Centralized |
| Cumulative 3-year cost | 41,000-140,000 EUR | 69,000-210,000 EUR |
| Competitive leverage | Low | Strong |
If your business fits standard tools, assemble. If your process IS your differentiation, custom pays off through productivity and zero friction.
The cost of avoided technical debt
| Item | Tool patchwork | Unified platform | Annual saving |
|---|---|---|---|
| Double entry (agent time) | 15 h/week | 2 h/week | ~28,000 EUR/yr |
| Re-keying errors | 3-5%/month | < 0.5% | ~12,000 EUR/yr |
| Integration maintenance | 20 days/yr | 5 days/yr | ~9,000 EUR/yr |
| New-hire onboarding | 3 weeks | 1 week | ~6,000 EUR/yr |
In this case, the unified platform saves roughly 55,000 EUR/yr in hidden costs. A 120,000 EUR investment pays back in a little over two years, excluding growth gains.
Mini case study
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Claire, CFO of a 60-person industrial SME in Lyon, juggles a CRM, two shared spreadsheets, a quoting tool and disconnected accounting. Cost of double entry and errors: ~4,500 EUR/month in wasted time. She invests 120,000 EUR in a unified platform delivered in 6 batches over 24 weeks. From batch 3 (synced quotes + stock), she saves 2,800 EUR/month. At full delivery, savings reach 4,500 EUR/month, or 54,000 EUR/yr. Payback: about 26 months, plus real-time margin visibility she never had.
FAQ
How much does a proper scoping document cost?
Professional scoping (workshops, process mapping, prioritized user stories) represents 5 to 12% of the project budget, or 5,000 to 18,000 EUR. It's the investment that prevents the most change requests later.
Why phase into batches rather than deliver all at once?
Phasing reduces risk and lets the value of the first batches fund the next. You validate direction every 4 to 6 weeks instead of discovering a gap at the end.
Custom or SaaS: how to decide?
Simple rule: if the process is your competitive advantage, build; if it's standard (payroll, emailing), subscribe. Most successful platforms blend both.
How long for a full vertical platform?
Between 16 and 32 weeks depending on modules and integrations. A first usable batch can ship as early as week 8, reassuring teams and kick-starting adoption.
What about the technical debt of my current tools?
It's quantified in the initial audit: double entry, errors, integration maintenance. It's often 40,000 to 60,000 EUR/yr in hidden costs, the strongest argument for investing in unification.
Let's scope your project. Describe your current processes, the tools to replace and your indicative budget (60,000-180,000 EUR): we'll structure the scoping document and propose a phased rollout. 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.
