The verdict in three sentences
The CIO of a mid-sized company who must take over an application built by a vendor that has gone out of business starts with a takeover audit costing 3,000 to 8,000 EUR excl. VAT, without which no maintenance quote is credible. After that, fixed-price maintenance (TMA) usually costs 15 to 25% of the initial development cost per year, time and materials is billed at 500 to 750 EUR excl. VAT per day, and a subscription blends the two. The right model depends on expected change volume, required SLAs (from 4 hours to 5 business days) and a reversibility clause so this never happens again.
Step 1: the takeover audit and what it must deliver
An orphaned application almost always hides surprises: dependencies not updated for three years, no tests, missing hosting credentials, no documentation. The audit prices these risks before you sign a maintenance contract.
| Audit area | What is checked | Deliverable | Share of audit budget |
|---|---|---|---|
| Access and ownership | Source code, Git repository, domain, hosting, third-party accounts | Inventory of recovered access | 10% |
| Code quality | Architecture, duplication, test coverage | Maintainability score | 25% |
| Security | Vulnerable dependencies, OWASP flaws, secrets handling | Ranked vulnerability list | 25% |
| Infrastructure | Servers, backups, end-of-life PHP, Node or Java versions | Upgrade plan | 15% |
| Documentation and data | Database schema, flows, business rules | Rebuilt minimum documentation | 15% |
| Takeover plan | Urgent fixes, remediation work | Prioritised, costed estimate | 10% |
For an application of 30,000 to 80,000 lines of code, allow 5 to 10 days of audit, i.e. 3,000 to 8,000 EUR excl. VAT. The remediation that follows (version upgrades, critical tests) often amounts to 10 to 20% of the initial cost, paid once.
Fixed price, time and materials or subscription: priced comparison
Once the application is stable, three contract models coexist on the French market.
| Criterion | Fixed-price TMA | Time and materials | Tiered subscription |
|---|---|---|---|
| 2026 price | 15 to 25% of initial cost per year | Daily rate 500 to 750 EUR excl. VAT | 1,500 to 6,000 EUR excl. VAT per month |
| What is included | Corrective, preventive, small changes within a set volume | Everything, at actual time spent | A number of days per month + SLAs |
| Budget predictability | High | Low | High |
| Flexibility on changes | Low beyond the volume | High | Medium (days carried over or not) |
| Response commitment | Contractual SLAs | Usually none | Contractual SLAs |
| Best fit | Stable app, few changes | One-off large change project | Living app, regular changes |
| Risk | Paying for little activity | Hours drift | Unused days lost |
For an application that cost 200,000 EUR to build, the annual fixed price therefore sits between 30,000 and 50,000 EUR excl. VAT. The same budget on time and materials at 650 EUR a day buys 46 to 77 days of work.
SLAs and reversibility: the clauses to negotiate
A maintenance contract without measurable service levels does not protect your production. SLAs are defined by severity, with a response time and a fix or workaround time.
| Severity | Example | Response | Fix or workaround | Usual penalty |
|---|---|---|---|---|
| Blocking | App down, invoicing stopped | 1 business hour | 4 business hours | 5% of monthly fee per hour late, capped |
| Major | Key function degraded, manual workaround possible | 4 business hours | 1 business day | 2% per day late |
| Minor | Display error, inaccurate report | 1 business day | 5 business days | None, or annual bonus-malus |
| Change request | New field, new export | 2 business days | Per approved estimate | Not applicable |
Reversibility is the lesson of your current situation: require the code to live in your own Git repository, hosting accounts to be in your name, documentation to be updated at each release, and 5 to 10 days of handover assistance at a pre-agreed price at contract end.
Mini case study
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Nicolas, CIO of a 600-employee distribution company in Nantes, inherits a customer returns tool built for 180,000 EUR whose vendor has closed down. He orders a 6,500 EUR excl. VAT audit: 3 critical vulnerabilities, framework out of support. Remediation is priced at 28,000 EUR excl. VAT.
He then compares two maintenance offers. Fixed price at 20%: 36,000 EUR excl. VAT per year. Subscription at 3,500 EUR a month including 5 days and a 4-hour SLA on blocking incidents: 42,000 EUR excl. VAT per year. Since he expects 4 to 5 days of changes a month to follow new reverse-logistics rules, the subscription avoids about 20 days of out-of-scope time and materials (13,000 EUR) and wins. Year-one budget: 6,500 + 28,000 + 42,000 = 76,500 EUR excl. VAT.
FAQ
How much does business application maintenance cost in 2026?
On a fixed price, 15 to 25% of the initial development cost per year. On time and materials, the daily rate is 500 to 750 EUR excl. VAT depending on seniority and technology.
Why audit before taking over an application?
Because no vendor can commit to SLAs without knowing the state of the code. A 3,000 to 8,000 EUR excl. VAT audit reveals flaws and prices remediation, often 10 to 20% of the initial cost.
What SLA should a critical application have?
A fix or workaround within 4 business hours for blocking incidents, 1 day for major ones and 5 days for minor ones. 24/7 on-call adds 20 to 40% to the fee.
What should a reversibility clause contain?
Ownership of code and access, up-to-date documentation and 5 to 10 days of handover assistance at a fixed price. It must apply whatever the reason the contract ends.
Fixed price or time and materials, how to choose?
If changes regularly exceed 3 to 4 days a month, a subscription or fixed price with included volume costs less. For a one-off project, time and materials stays the most flexible.
Let's scope your project. Tell us your application's technology, age and initial cost, and we will propose a takeover audit between 3,000 and 8,000 EUR excl. VAT followed by a maintenance offer with SLAs. 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.
