The verdict in three sentences
A well-written requirements spec is worth its weight in gold: it turns a fuzzy SIS project into a costed build-vs-buy decision. For a multi-school group, custom at 50,000-110,000 EUR is justified when no market SIS (8-16 EUR/student/year) covers your enrollment, grading and billing rules without heavy re-keying. The grid below structures your functional, technical and compliance requirements before you go to market.
Requirements spec: what to frame
For each requirement, set a priority (must/should/nice) before any quote.
| Domain | Typical requirement | Priority |
|---|---|---|
| Enrollment | Registrations, records, multi-site classes | Must |
| Assessment | Grades, report cards, competencies | Must |
| Family billing | Schedules, bursaries, direct debit | Must |
| Communication | Parent messaging, notifications | Should |
| Integrations | LMS, payroll, accounting | Should |
| Compliance | GDPR, minors' data, EU hosting | Must |
| Reporting | Leadership dashboards | Nice |
Build vs buy: the 2026 costed comparison
Orders of magnitude for a 3-school group, 1,800 students combined.
| Criterion | Market SIS | Custom |
|---|---|---|
| Annual / upfront cost | 8-16 EUR/student/year | 50,000-110,000 EUR |
| Example 1,800 students | 14,400-28,800 EUR/year | one-time build + maintenance |
| Timeline | 6-10 weeks | 14-22 weeks |
| Maintenance | included in subscription | 12%/year of build |
| Multi-tool consolidation | Partial | Full |
| Fit to internal rules | Low | High |
| Code & data ownership | No | Yes |
Mini case study
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Nadia, CIO of a 3-school private group in Lille (1,800 students), runs a SIS, a billing tool and a grade spreadsheet with three daily re-keyings. She invests 84,000 EUR in a custom platform, maintenance 12%/year (10,080 EUR). Consolidation removes double entry and redeploys 2 administrative FTEs (about 76,000 EUR/year loaded) toward family support. Payback in roughly 14 months.
FAQ
What should an SIS requirements spec contain? Prioritized functional scope (must/should/nice), technical constraints (LMS/payroll/accounting integrations), GDPR requirements, volumes (students, sites) and acceptance criteria. This document drives the quality of the quotes you receive.
Build or buy: how to decide? Buy if a market SIS covers over 80% of your musts without re-keying. Build once multi-tool consolidation and your specific rules dominate, typically beyond 1,500-2,000 students.
What custom budget to plan? 2026 order of magnitude: 50,000-110,000 EUR for a multi-site group, maintenance 12%/year. A production core can start at 30,000-40,000 EUR.
What timeline for a multi-school group? 14-22 weeks for the full platform, with a switch aligned to the school calendar. Historical migration adds 2-4 weeks.
How to secure minors' data? EU hosting, minimization, traced parental consent, encryption and a GDPR audit in acceptance. Compliance must be a must, not an option.
Let's scope your project. Send your requirements spec (or outline) and target budget (50,000-110,000 EUR) and we assess build vs buy and price the scope. 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.
