Web App Maintenance and Support: What the Contract Covers and What It Costs (2026)

The verdict in three sentences

An application is alive: without maintenance and support, it accumulates vulnerabilities, technical debt and obsolescence until it forces a redesign costing 20 to 50 % of the initial budget within three years. A good contract costs 8 to 20 % of development cost per year, i.e. 300-1,500 EUR/month, and covers corrective, preventive, light enhancements and a recovery SLA. Never sign a support contract without a reversibility clause and code access: it is your only protection against lock-in.

Fixed fee, T&M or SLA: three logics

Each model fits a different need profile. 2026 orders of magnitude, French/EU market, ex-VAT.

A fixed fee suits most SMEs: predictable budget and common incidents covered. T&M serves when you evolve the tool a lot. An SLA is essential for a critical app whose downtime is costly.

SLA levels and the hidden cost of neglect

Conversely, leaving an app unmaintained is silently expensive: outdated dependencies, unpatched vulnerabilities, browser incompatibilities. At three years, the upgrade or redesign runs 20 to 50 % of the initial budget, not counting the GDPR risk of an exploited flaw.

Mini case study

Nadia, CIO of a 60-person services SME in Toulouse, must renew maintenance on her customer portal built for 55,000 EUR. Unmaintained for 18 months, the portal is accumulating update backlogs. A 900 EUR/month fee (i.e. 10,800 EUR/year, about 20 % of dev) would cover corrective, preventive and small enhancements, with a 4 h critical SLA. Without a contract she estimates the three-year redesign risk at 40 % of 55,000, i.e. 22,000 EUR, plus GDPR exposure. Over three years, maintenance costs her 32,400 EUR but averts a likely redesign and secures compliance: the trade-off clearly favours the contract.

FAQ

How much does maintenance cost in 2026?

Expect 8 to 20 % of development cost per year, i.e. a fee of 300-1,500 EUR/month depending on scope and criticality. A 50,000 EUR app typically costs around 5,000-10,000 EUR/year to maintain.

What is the difference between corrective and enhancement?

Corrective fixes what is broken (bugs, vulnerabilities); enhancement adds features. A good fee includes corrective plus a small enhancement quota; large developments are billed T&M or as projects.

What is a 4-hour recovery SLA?

It is the commitment to restore a blocking incident within 4 hours, often with penalties. This level justifies a surcharge (1,000-3,000 EUR/month) and is reserved for critical apps.

Why require a reversibility clause?

Because it guarantees access to documented source code and hosting so you can switch vendors without rebuilding. Without it, a takeover costs 30 to 60 % of the initial budget.

What does an unmaintained app risk?

It accumulates technical debt, vulnerabilities and incompatibilities. At three years, the upgrade or redesign reaches 20 to 50 % of the initial budget, not counting GDPR risk and downtime.

Let's scope your project. Tell us your app's development cost and criticality, and we will propose a support contract (fixed fee, T&M or SLA) with reversibility included. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.