The verdict in three sentences
A maintenance contract generally costs 12 to 20 % of the build cost per year and protects your investment against bugs, vulnerabilities and obsolescence. It covers corrective work (bugs), preventive work (security, updates) and often hosting, but enhancements (new features) are almost always billed separately. Without a written SLA, you pay a vague retainer: demand quantified intervention times.
What a typical contract covers
Not all maintenance is the same. Here are the three types of intervention and their usual contractual treatment.
| Type | Content | Included in the contract? |
|---|---|---|
| Corrective | Bug fixing | Yes |
| Preventive | Security, updates, backups | Yes |
| Adaptive | Browser compatibility, dependencies | Usually yes |
| Enhancement | New features | No, billed separately |
| Hosting | Server, CDN, monitoring | Per contract |
| Support | User assistance | Per level |
The most common confusion concerns enhancements: adding a feature is not maintenance and is billed at day rate or as a dedicated package.
Cost and SLA by level
The 2026 ranges vary with criticality and guaranteed response time.
| Level | % of build / year | Critical-fix time | Indicative monthly cost |
|---|---|---|---|
| Essential | 10-12 % | 48-72 h | 50,000 FCFA / 76 EUR |
| Standard | 12-16 % | 24 h | 100,000 FCFA / 152 EUR |
| Premium | 16-20 % | 4 business h | 200,000 FCFA / 305 EUR |
| Critical 24/7 | 20-25 % | 1-2 h | On quote |
A showcase site is fine with an essential contract; a sales platform requires a short SLA, since every hour of downtime costs revenue.
Mini case study
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Me Diop, partner at a firm in Dakar, runs a client portal built for 6,000,000 FCFA (9,150 EUR). With no maintenance, an unpatched security flaw over the summer exposed client data and cost an emergency fix of 900,000 FCFA. He now subscribes to a Standard contract at 100,000 FCFA/month (1,200,000 FCFA/year, i.e. 20 % of the build): monthly security updates, backups and 24-hour fixes. The annual cost is lower than a single major incident avoided.
FAQ
Is a maintenance contract really essential?
Yes for any site connected to data or payments. Without maintenance, vulnerabilities pile up and an emergency fix often costs more than a year of maintenance.
Why aren't enhancements included?
Because they are new development, not maintenance. Every new feature is quoted separately, at day rate or as a package, to avoid scope abuse.
What to check in a contract?
Intervention times (SLA), the in/out scope, backup frequency, reversibility and whether hosting is included. A retainer with no written SLA is worthless.
Can the percentage be negotiated?
Yes, depending on criticality and volume. A multi-year commitment or a narrow scope lowers the rate; a short SLA and 24/7 support raise it.
Let's scope your project. State the application type, its criticality and the SLA level you want: we will quote a suitable maintenance contract with a clear 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.
