Web applications · Next.js & Node.js

Custom web app development

VirtuoLab is a software agency in Papendrecht which builds custom web apps: customer portals, booking systems, dashboards and internal tools which run in the browser, without the App Store or Google Play. VirtuoLab builds every web app in-house with Next.js, TypeScript and PostgreSQL, so one developer knows the entire system. In 2026, a custom web app from VirtuoLab costs €5,000 to €50,000. A simple first version takes 3 to 6 weeks. For example, a customer portal for 500 customers can replace many phone calls and emails. You receive a fixed price upfront, speak directly with the developer and own the source code and the data.

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Price indication
€5,000 – €50,000 (enterprise platforms from €50,000)
Timeline
3–6 weeks (simple) to 12–24 weeks (complex)
Stack
Next.js, React, TypeScript, Node.js, PostgreSQL, Docker, AWS
Service area
On location in the Drechtsteden and Rotterdam; online across the Netherlands, Belgium and Germany
Contact
Directly with the developer

What is a web app, and what does VirtuoLab build?

A web app is software which runs in the browser and lets users log in, enter data and complete tasks, instead of only reading pages. A website informs, while a web app does work. VirtuoLab, a software agency in Papendrecht, builds custom web apps for small and medium-sized businesses. Typical projects are a customer portal with orders and invoices, a booking or planning system, or a quote calculator. Additionally, an internal tool which replaces a pile of Microsoft Excel sheets, or a dashboard with live figures, is a web app too. VirtuoLab builds the whole application with Next.js: the interface, the database, the user roles and the links to systems such as Exact Online or Mollie. For example, the Smart Calculator demo on virtuolab.dev shows a mortgage calculator with real-time charts. Phone support matters: according to StatCounter, phones generated about 65% of Dutch web traffic in September 2026. A web app works on desktop, tablet and phone, and every update reaches all users at once.

What does it cost to have a web app built in 2026?

A custom web app costs between €5,000 and €50,000 in 2026, and an enterprise platform starts at €50,000. Every amount is an indication, and VirtuoLab sets the exact price after a free intake call, before any development starts. A simple web app with one main function, a login and a few screens costs €5,000 to €10,000. A mid-sized web app with several user roles, integrations and reports costs €10,000 to €25,000. A complex web app or SaaS platform costs €25,000 to €50,000. Four factors drive the price. First, the number of features and screens. Second, the number of user roles and permissions. Third, the integrations with Exact Online, a payment provider such as Mollie or other outside systems. Finally, the demands on scale and security: a tool for 10 people needs a lighter setup than a portal for 5,000 customers. In practice, a smaller first version with room to grow keeps the budget under control.

How long does it take to build a web app with VirtuoLab?

A simple web app, such as an internal tool for 20 people, takes 3 to 6 weeks at VirtuoLab. A mid-sized web app takes 6 to 12 weeks, and a complex web app 12 to 24 weeks. An enterprise platform takes 24 weeks or more. Every project runs in four steps. Step 1 is the intake and scope: in a free call, goals, users and must-have features turn into a written scope with a fixed price. Step 2 is design and validation, where the screens and the data model are designed by VirtuoLab and approved by you before building starts. Step 3 is building and testing in short sprints, with a working demo after every sprint. Step 4 is the launch and support: the web app goes live, hosted with Docker on AWS or another provider. Finally, decisions during the project affect the timeline most. In practice, a pilot group of 10 users who test each demo quickly keeps the project on schedule.

Which technology does VirtuoLab use for web apps, and why?

VirtuoLab builds web apps with Next.js, React and TypeScript in the browser, Node.js on the server and PostgreSQL as the database. Next.js is a React framework by Vercel, suited to both public pages and logged-in applications. The choice has three reasons. First, TypeScript catches type errors before the code runs, which keeps changes safe years later. Second, PostgreSQL is a proven open-source database with strong support for relations, transactions and JSON data. Third, server-side rendering makes public pages load fast and stay readable for Google. For live updates, VirtuoLab adds WebSockets, and for integrations with other systems, REST or GraphQL APIs. The application runs in Docker containers, for example on AWS, so moving to another hosting provider remains possible. Every part of the stack is widely used, according to the Stack Overflow Developer Survey 2025. In the survey, 44.7% of developers had used React and 55.6% had used PostgreSQL, so another developer can take over the code without a rewrite.

Why have your web app built by VirtuoLab?

VirtuoLab is a one-person software agency, which means the developer who builds your web app is also your only contact. First, you work directly with Mustafa Kose, the founder and developer, without account managers or project managers in between. Second, VirtuoLab agrees a fixed price before development starts, so the budget does not move during the build. Third, you own the source code and the data after delivery, so future changes never depend on help from VirtuoLab. Finally, short sprints with demos show progress throughout the project. Meetings take place on location in the Drechtsteden and Rotterdam or online, in Dutch, English or German, Monday to Friday from 09:00 to 18:00. There are honest limits as well. In practice, one developer has limited capacity and is not available around the clock. A larger agency therefore fits better for an enterprise platform for 5,000 users with a hard deadline, or when you want a team of 5 people with a separate designer, tester and project manager.

Which businesses is a custom web app a good fit for?

A custom web app from VirtuoLab is a good fit for businesses whose work no longer fits in Microsoft Excel, email and standard software. A common signal is data typed into three systems by hand. Other signals are customers who call for information a portal could show, and a standard package which covers only part of the process. Startups use a web app built with Next.js as an MVP to test a product with the first 50 customers before investing in a full platform. The budget for a simple tool starts at €5,000. VirtuoLab works for small and medium-sized businesses across the Netherlands, Belgium and Germany. Custom software is not always the smart choice, though. When an existing package such as Exact Online or a booking platform already fits the process, a subscription is usually cheaper. When visitors only need information, a business website of €2,000 to €8,000 is enough. In practice, VirtuoLab points out the cheaper option openly in the free intake call.

Our own products

Software we build and run ourselves

FiscalDesk and Bouwklok are VirtuoLab products. Both are live and can be tried. The images below are recordings and screens from the software itself.

Accounting software for accounting firms

FiscalDesk

  • Reads and books invoices automatically
  • Only exceptions reach the accountant
  • App for clients to scan receipts
Next.jsReactPostgreSQLClaude (Anthropic)
View the projectfiscaldesk.nl

Frequently Asked Questions

What is the difference between a web app and a mobile app?

A web app runs in the browser on any device, while a mobile app is installed from the Apple App Store or Google Play. The difference affects cost, reach and features. A web app built with Next.js needs one codebase for desktop, tablet and phone, and every update is live immediately without store approval. A mobile app gets deeper access to phone features such as push notifications, the camera and Bluetooth, and sits as an icon on the home screen. At VirtuoLab, a simple web app costs €5,000 to €10,000, and a simple mobile app costs €10,000 to €20,000. A progressive web app sits in between: a web app which users can add to the home screen, powered by a service worker. The technique is common: according to the HTTP Archive Web Almanac 2025, 28.9% of the top 1,000 mobile pages use a service worker. In practice, many projects first launch as a web app and add a React Native app later.

Can a web app connect to Exact Online, Mollie or my CRM?

Yes, in 2026 a web app from VirtuoLab can connect to almost any system with an API, from accounting software to payment providers and CRM systems. For example, Exact Online or Moneybird handle invoices, Mollie or Stripe handle payments, and HubSpot or Salesforce hold customer data. An API is a fixed connection point through which systems exchange data, so nobody types orders twice. A portal for 300 customers can, for instance, fetch invoices automatically through a link with Exact Online. The cost depends on the integration. A simple API link costs €1,500 to €4,000, and a custom REST API costs €5,000 to €15,000. A complex integration layer with several systems costs €15,000 to €30,000. Within a web app project, the links are part of the overall fixed price. First, VirtuoLab checks the documentation and limits of each API, because some providers restrict requests or charge for access. Systems without an API, such as old desktop software, sometimes need a file export as a workaround.

Should I choose a custom web app or an existing SaaS tool?

An existing SaaS tool is the better choice when the tool covers your process well. A custom web app is the better choice when the process itself sets your business apart. First, consider cost. Standard tools are cheap to start with, but with per-user fees, a team of 20 people pays 20 times the single-seat price. A custom web app costs more upfront, fits the way your team works, carries no per-user licence fees and starts at €5,000. Second, consider ownership. With a custom web app from VirtuoLab, you own the code and the data. A SaaS vendor, by contrast, decides on prices, features and the future of the product. For example, a common middle route in 2026 is a standard tool for generic work, such as accounting with Exact Online, plus a custom web app for the core process. VirtuoLab discusses the choice openly in the free intake call, with both routes side by side.

Can VirtuoLab build a web app in phases?

Yes, a web app from VirtuoLab can be built in phases, and for many businesses a phased route is the smartest option. Phase 1 is a first version with the core function, for example a portal for 200 customers with a login and an order overview. A simple web app like the portal takes 3 to 6 weeks and costs €5,000 to €10,000. Real users, such as the first 50 customers, then show which features matter next. Every following phase gets its own scope and fixed price before work starts, so you keep control of the total budget. The setup with Next.js and PostgreSQL is built to grow from the start, which avoids a rebuild after the first version. Because you own the code, a later phase can also go to another developer. In practice, a phased approach lowers the risk of building features which nobody uses.