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Voltra
FR

Web app

A web application built to scale, not to limp along

A custom web application — SaaS, internal dashboard, client tool — needs to hold up the day your business takes off, not just on launch day. We build robust web applications in Next.js and React, with authentication, billing and architecture designed from the start to grow with you, with no full rewrite six months later. An independent studio based in Fleurus, Belgium, we build for companies in Charleroi, Namur, Mons and across Wallonia.

See our work
  • Architecture designed to scale
  • Authentication, billing and user roles included
  • We can take over a fragile existing application

The problem

What a poorly architected application costs you

A patched-together tool works fine on day one. The problem shows up when it has to grow.

Our answer

An architecture that lasts

Every web application we deliver is designed to support growth, not just to work in a demo.

  • Architecture built to last

    Clear structure, separated responsibilities, well-designed database: your application supports growth in user numbers without a full rebuild.

  • Authentication and role management

    Secure login, fine-grained permission management by role, two-factor authentication if needed: security best practices built in from day one.

  • Integrated billing and subscriptions

    Connected to Stripe or an equivalent to handle subscriptions, free trials, plan changes and compliant invoices, without building from scratch.

  • Clear, actionable dashboard

    Your users and your team see the information that matters, presented simply. A good dashboard saves time on every login.

  • Ready to scale

    Infrastructure and code designed to absorb rapid user growth without performance loss or service interruption.

  • Taking over existing applications

    We audit and take over fragile existing applications: fixing technical debt, securing the system, then evolving it calmly, without a full rebuild unless it's necessary.

Process

From call to launch in 4 steps

  1. 01

    Discovery

    A workshop to define essential features, user roles and required integrations. Firm quote within 48h.

  2. 02

    Design & architecture

    Mockups of key screens and definition of the technical architecture and database. Two rounds of revisions included.

  3. 03

    Development

    Feature development, authentication and billing integration, testing. Tracked on a demo environment.

  4. 04

    Launch & follow-up

    Production deployment, data migration if needed, team training. Then 30 days of included bug-fix warranty.

Budget

How much does a custom web application cost?

A firm price after scoping. The range depends on the number of features, integrations, and architecture complexity.

from

€5,900

Prices exclude VAT. Custom web application, authentication and billing included. Free detailed quote within 48h.

  • Dedicated technical architecture
  • Authentication and role management
  • Billing and subscription integration
  • Custom dashboard
  • 30 days of included bug-fix warranty
Get a free quote

FAQ

Your questions about web applications

A custom web application starts at €5,900 excl. VAT for a functional base with authentication and a dashboard. A full SaaS with subscription billing, advanced role management and multiple integrations generally falls between €11,000 and €28,000. The firm quote is delivered within 48h after scoping your needs.

A SaaS MVP with essential features takes eight to twelve weeks. A more complete application, with billing, fine-grained role management and third-party integrations, takes three to six months. We often recommend starting with a minimal base to validate the market before investing in advanced features.

Yes, it's a common request. We start with an audit of the existing code and architecture to identify risks and technical debt, then propose either a gradual takeover or a targeted rebuild depending on the project's state. The goal is always to preserve what works and secure the rest.

We integrate proven payment solutions like Stripe to handle subscriptions, free trials, plan changes and compliant invoices. This avoids building complex, sensitive billing logic from scratch, while guaranteeing reliable recurring payments and cash-flow tracking.

Yes, that's a design criterion from day one. We choose an architecture and infrastructure capable of absorbing rapid growth, with a well-structured database and scaling mechanisms. We also load-test before launch to avoid surprises during usage spikes.

Yes, entirely. The source code, documentation and access credentials are handed over at delivery, with no hidden dependency on our agency. You can move to another team if you want. We offer an optional maintenance plan, never a contractual obligation to stay with us.

Our commitments, in writing

  • Quote within 48h

    A detailed, firm estimate — not a vague range.

  • Code delivered, code you own

    You walk away with the full Git repository. No hidden dependencies.

  • Maintenance covered

    Fixes, updates, and monitoring after launch.

  • Revisions included

    Every phase includes planned rounds of feedback in the quote.

Your project deserves an architecture built to last

Describe your application and your growth goals: a detailed, firm quote within 48h, free.

Chat on WhatsApp

Response within 24h