The verdict in three sentences
In Paris, the price of a custom web app depends first on functional complexity, not on the tech: a simple CRUD starts at EUR 25,000 excl. VAT, a workflow tool climbs to EUR 60,000–110,000 excl. VAT, and a real-time multi-role platform tops EUR 180,000 excl. VAT. The second driver is the day rate (EUR 550–850 excl. VAT at a Paris agency) multiplied by team size and the number of sprints. What blows up the quote is almost never the code itself, but third-party integrations, compliance requirements and a vague requirements spec.
2026 price grid by complexity
The ranges below are a 2026 order of magnitude for a Paris agency or studio, excluding maintenance and third-party licences.
| App type | Typical scope | Duration | Price EUR excl. VAT |
|---|---|---|---|
| Simple CRUD | Auth, tables, forms, export | 6-8 wks | 25,000 – 45,000 |
| Workflow app | Roles, approvals, notifications, PDF | 10-14 wks | 60,000 – 110,000 |
| Data / reporting app | Dashboards, aggregations, connectors | 12-16 wks | 80,000 – 140,000 |
| Real-time / collaborative | WebSocket, presence, multi-role | 16-24 wks | 130,000 – 200,000+ |
| Multi-tenant platform | Client isolation, billing, API | 20-30 wks | 160,000 – 280,000+ |
A serious quote always breaks out these lines separately: discovery, UX/UI design, front-end development, back-end, integrations, QA, go-live.
What actually makes up the day rate and team
The day rate varies sharply by profile and engagement model. Here are the 2026 benchmarks on the Paris market.
| Profile | Freelance day rate | Agency day rate | Typical project load |
|---|---|---|---|
| Junior developer | EUR 350 – 450 | EUR 500 – 600 | 20-40% |
| Senior developer | EUR 550 – 700 | EUR 700 – 850 | 30-50% |
| Lead / architect | EUR 700 – 900 | EUR 900 – 1,100 | 10-20% |
| Product / PM | EUR 500 – 650 | EUR 650 – 800 | 10-15% |
| UX / UI designer | EUR 450 – 600 | EUR 600 – 750 | 10-20% |
A classic team for a workflow app gathers 1 lead, 2 developers, 1 designer and a part-time product manager. Over 12 weeks, that is roughly 180 to 220 person-days, the core of the budget. The factors that blow up the quote: ERP/accounting integrations (+EUR 8,000 to 25,000), GDPR/health-data hosting requirements (+EUR 10,000 to 30,000), legacy data migration, and above all a spec that shifts mid-project.
Mini case study
Marc, IT director of a B2B distribution SME in Paris (85 staff), wants to replace Excel order tracking with a workflow web app. Scope: 4 roles, 3-level approval, email notifications, accounting export, management dashboard. The agency proposes 165 person-days at a blended day rate of EUR 720, i.e. EUR 118,800 excl. VAT, plus EUR 12,000 to integrate their accounting software. Marc trades off: he defers the management dashboard (–18 days) to phase 2 and signs phase 1 at EUR 95,760 excl. VAT over 11 weeks. Target gain: 15 hrs/week saved on data entry and tracking, about EUR 30,000/year of admin time, for a payback under 3.5 years excluding commercial gains.
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FAQ
What is the minimum budget for a real custom web app in Paris?
Budget at least EUR 25,000 excl. VAT for a serious CRUD with authentication, permission management and go-live. Below that, you fund a prototype, not a production-grade application.
Why do two quotes for the same project differ by 2x?
Because the implicit scope differs: QA, security, documentation, data migration and day rate are not always included. A gap of EUR 45,000 to 90,000 excl. VAT almost always reflects a spec read differently.
Should I pay fixed-price or time-and-materials?
Fixed price locks a frozen scope (ideal for a scoped MVP); time-and-materials, billed at the day rate (EUR 550–850), suits evolving scopes. Many projects combine fixed price for the core and T&M for enhancements.
How much is annual maintenance?
Budget 15 to 25% of the development cost per year, i.e. EUR 15,000 to 30,000/year for a EUR 110,000 app, including fixes, version upgrades and minor enhancements.
How long until the first go-live?
For a workflow app, 10 to 14 weeks if the spec is stable; each major mid-project change typically adds 1 to 3 weeks and EUR 8,000 to 20,000 excl. VAT.
Let's scope your project. Describe your roles, workflows and target integrations, with an indicative budget and desired timeline, and we will price each line separately. 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.
