B2B Website Maintenance & SLA Contract Cost (2026)

The verdict in three sentences

A well-scoped application maintenance (TMA) contract costs between 150 and 1,200 EUR/month depending on whether it covers corrective work only or evolutive development, and it protects an initial investment often above 20,000 EUR. The critical point is not price but the SLA: guaranteed recovery time, 99.9% uptime and a black-and-white scope of what's included versus excluded. A B2B website without active maintenance accrues security debt, performance regressions and lost Google rankings within months.

Service levels and their 2026 costs

Maintenance splits into three blocks you must separate in the quote: corrective (bugs, security), evolutive (new features) and managed hosting. Here are 2026 orders of magnitude on the European market.

A full TMA + hosting package for an industrial SME runs around 500 to 900 EUR/month in 2026. Add on-call only if your site generates revenue over the weekend.

Fixed fee vs time-and-materials

A fixed fee gives budget predictability; time-and-materials suits irregular needs. A senior developer's hourly rate sits between 70 and 110 EUR in 2026.

Clause to demand: rollover of unused hours over 1 to 3 months, otherwise you pay for a dormant package.

Mini case study

Claire, CFO of an industrial SME in Lyon (85 staff), is torn between time-and-materials and a fixed fee for her redesigned showcase site (24,000 EUR build). On T&M, her average 6 h/month at 95 EUR costs 570 EUR, but a security incident in a heavy month can spike the bill to 1,400 EUR. She signs a 750 EUR/month fixed fee including 6 h, managed hosting and an 8-business-hour recovery SLA. Over the year she caps her budget at 9,000 EUR instead of a 12,000-15,000 EUR risk, and secures the availability of her main acquisition channel.

FAQ

What uptime should I demand in the SLA? Aim for 99.9%, i.e. roughly 8.8 hours of downtime per year maximum. Below 99.5%, your site can be down more than 43 h/year, unacceptable for a B2B commercial channel.

What recovery time should I negotiate? Between 4 and 24 business hours by criticality. A site with active quote forms justifies a 4-to-8-hour recovery guarantee; a purely editorial site can tolerate 24 h.

Does maintenance include new features? Not by default. Corrective TMA covers bugs and security; any new feature is evolutive work, billed 400-1,200 EUR/month or T&M at 70-110 EUR/h. Have the excluded scope listed.

What happens without maintenance? An un-updated CMS becomes vulnerable within 3 to 6 months, Core Web Vitals degrade and Google drops your rankings. Bringing it back up to standard often exceeds 2,000-5,000 EUR.

Can I switch providers easily? Yes if the contract includes a reversibility clause: code access, technical documentation and hosting access transfer with no hidden fees. Demand it at signature.

Let's scope your project. Tell us about your site, its CMS and the service level you want (corrective, evolutive, on-call): we'll frame a TMA contract with a costed SLA. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.