In short: building a web application in the Netherlands costs between €12,500 for a compact customer portal and €150,000 or more for a multi-tenant SaaS platform in 2026. Most small and mid-sized business web apps land between €25,000 and €60,000 excl. VAT. Functionality, integrations, roles and security set the price. After launch, budget 15 to 20% of the build cost per year for hosting, maintenance and further development.
Web app, website or mobile app?
A website informs: visitors read, compare and get in touch. A web application does something: users log in, enter data, order, schedule, calculate or share. The difference is not the technology but the logic behind it. As soon as you need accounts, roles, a database and business rules, you are building software, not a site.
A mobile app is a third category: an application installed through the App Store or Google Play. It makes sense when you need the camera, GPS, push notifications or offline use. In every other case a web app is cheaper, live sooner and usable everywhere without installation, including on a phone. If you are unsure, read what it costs to build an app and put the figures side by side.
Typical web applications for SMEs: a customer portal where clients view orders, invoices and documents, a scheduling tool for field staff, a member area, a quote generator, an internal dashboard or a SaaS product you sell to third parties.
Price table: MVP, customer portal and SaaS platform
| Type of web application | What you get | Guide price 2026 (excl. VAT) | Timeline |
|---|---|---|---|
| Internal tool or calculator | 1–3 screens, 1 role, no integrations, replaces a spreadsheet | €8,000 – 15,000 | 3–6 weeks |
| Customer portal | Accounts, roles, documents, orders, 1–2 integrations (ERP, accounting) | €12,500 – 35,000 | 6–10 weeks |
| SaaS MVP | Onboarding, subscriptions, payments, admin, 1 core feature done well | €25,000 – 60,000 | 8–14 weeks |
| Multi-tenant platform | Multiple organizations, permissions model, API, integrations, audit logging | €50,000 – 150,000+ | 12–20 weeks |
| Enterprise custom build | Complex workflows, legacy migration, compliance (NEN 7510, ISO 27001) | €150,000 – 500,000+ | 6–18 months |
Traditional Dutch agencies charge €100 to €150 per hour and put 3 to 6 people on a project. A studio working with 1 senior maker and AI tooling delivers the same functionality 30 to 50% cheaper, with a shorter timeline. The bottom of each range is based on that model, the top on agency quotes we see in 2026.
Where the budget goes
A web application is rarely 1 big cost item. The budget splits roughly like this:
- Discovery and design (15–20%). User roles, processes, data model and a clickable prototype. This is where you earn the most back: a mistake found in a prototype costs 10 times less than the same mistake in code.
- Core functionality (35–45%). The screens and logic the app exists for. Every extra screen with its own logic costs €1,500 to €5,000.
- Accounts, roles and security (10–15%). Login, password reset, two-factor authentication, SSO through Microsoft or Google, permissions per role. Standard work, but work that has to be flawless.
- Integrations (10–20%). Exact Online, AFAS, a CRM, a payment provider, an email service. Budget €1,500 to €5,000 per integration, more for systems without a decent API.
- Testing, launch and documentation (10%). Automated tests, security check, migration of existing data, handover.
What drives the price up unexpectedly: reports with many filters, multiple languages, offline use, importing messy historical data and 'small' wishes such as a custom brand theme per client.
Stack choices and what they cost
The technology determines less of the build price than people think, but a great deal of the cost afterwards.
- Frontend and backend. We build in Node.js with Next.js, TypeScript and a REST or GraphQL API. Large talent pool, excellent tooling, no license fees. Alternatives such as Laravel (PHP) or .NET are just as good; pick what your future maintainer can support.
- Database. PostgreSQL is the default choice in 2026: open source, reliable and suitable from 10 to 10 million users. Managed hosting costs €15 to €100 per month at Neon, Supabase or a European provider such as Scaleway.
- Hosting. A Node.js app runs from €20 per month on a VPS at Hetzner or TransIP, or serverless on Vercel and Cloudflare. If your data must stay in the EU, choose a European cloud; for healthcare and for legal and financial firms that is often a hard requirement.
- Low-code. Bubble, Retool or Power Apps are cheaper to build (€5,000 to €15,000) but more expensive in licenses (€30 to €100 per user per month) and limited in ownership and export. Fine for internal tools up to 20 users, risky for a product you sell. The trade-off is covered in custom software vs off-the-shelf.
From idea to MVP in 8 weeks
This is what a realistic plan looks like for a customer portal or SaaS MVP:
- Week 1: discovery. Roles, processes and data model on paper. What is the one feature users need every day? Everything around it goes to the backlog.
- Week 2: prototype. Clickable design in Figma, tested with 3 to 5 real users. This is where you cut 30% of the wish list.
- Weeks 3–6: build in sprints. A working version on a test environment every week. You click through it on your own laptop, not in a presentation.
- Week 7: integrations and data. Connect the ERP or accounting system, import existing data, set up emails and notifications.
- Week 8: testing and launch. Security scan against the OWASP Top 10, performance test, handover with documentation, monitoring switched on.
After launch the real work starts: users give feedback and the backlog from week 2 is picked up in two-week releases.
Running costs and scalability
Budget 15 to 20% of the build cost per year. For a €30,000 web app that is €4,500 to €6,000 per year, spread across:
- Hosting and database: €50 to €300 per month, growing with usage.
- Maintenance and security updates: €250 to €950 per month for dependency updates, monitoring, backups and a support SLA.
- Further development: in practice the largest item. A fixed day per month costs €800 to €1,200; a continuous stream through custom software starts at €3,950 per month.
- External services: transactional email, payments through Mollie or Stripe, error monitoring, together €20 to €200 per month.
Scalability in 2026 is mostly an architecture question, not a hardware question. A well-built Node.js app on PostgreSQL scales to tens of thousands of users without a rebuild. What is expensive: adding multi-tenancy afterwards when you first built for 1 organization. Decide that in week 1.
Ownership of code and data
Three agreements that belong in every contract:
- The code is yours. Full transfer of copyright on payment, repository in your GitHub account, no hidden dependency on an agency-owned framework.
- The data is yours. Database in your cloud account, or at minimum an export at any time. A data processing agreement under the GDPR is mandatory as soon as the app handles personal data, which is almost always.
- The accounts are yours. Hosting, domain, email service and payment provider in your company's name. We get access, you keep the keys.
An agency that 'licenses the software to you' is selling a subscription with termination risk. For an internal tool that can be acceptable; for a product your revenue depends on, never.
Example: customer portal for a wholesaler
A technical wholesaler with 400 business customers and 6 inside-sales staff received 80 emails a day asking 'where is my order' and 'please resend the invoice'. The portal had to show order status, invoices, returns and repeat orders, connected to Exact Online.
- Discovery and prototype, 3 user roles: €3,500
- Accounts, SSO for key accounts, permissions model: €3,000
- Order overview, invoices, returns, repeat ordering: €9,500
- Exact Online integration (orders, invoices, customers, 2-way): €4,000
- Email notifications, PDF generation, import of 3 years of history: €2,500
- Testing, OWASP check, launch, documentation, 30 days of aftercare: €2,500
Total: €25,000 excl. VAT, live after 9 weeks. Result after 3 months: 70% fewer status emails and 2 FTE of inside sales freed up for selling. Running costs: €120 hosting and €495 maintenance per month.
RABZI estimate: a web application from RABZI starts at €12,500 excl. VAT (Launch: portal or internal tool, live in 6 to 10 weeks), from €24,500 for Growth (SaaS MVP with accounts, subscriptions and integrations) and from €49,500 for Flagship (multi-tenant platform with API and audit logging). Fixed price per phase, a senior maker at the helm, code and data yours. See web applications and platforms, our security approach or the full pricing.
Frequently asked questions
How much does a simple web application cost? An internal tool with 1 role and 2 to 3 screens, such as a time-tracking or calculation tool that replaces a spreadsheet, costs €8,000 to €15,000 excl. VAT and is live in 3 to 6 weeks. As soon as customers log in or an integration with your accounting system is added, you start around €12,500.
How long does it take to build a web application? A customer portal or MVP takes 6 to 10 weeks at a compact studio and 3 to 6 months at a traditional agency. The biggest delays are unclear processes and waiting for access to systems such as your ERP. Arrange API access before the kickoff.
Is building a SaaS realistic for a small or mid-sized business? Yes, provided you start small. An MVP with 1 core feature, subscriptions through Mollie or Stripe and an admin area costs €25,000 to €60,000. Test it with 10 paying customers before investing in multi-tenancy, APIs and integrations.
Can someone else maintain the app later? Only if the code is yours, built in a mainstream stack and documented. Ask every bidder about the repository, the stack and whether another developer could continue without a briefing. We deliver a technical handover as standard.
Conclusion
Building a web application in 2026 costs €12,500 to €35,000 for a customer portal, €25,000 to €60,000 for a SaaS MVP and €50,000 or more for a platform serving multiple organizations. Start with the one feature users need every day, choose a mainstream stack and put ownership of code and data in writing. Want to know what your web application would cost? Book an intro call and you will have an estimate with a fixed price and schedule within 2 business days.