The cost of a custom web app in 2026 depends less on the number of screens than on business complexity, integrations, data, and reliability. Two similar-looking projects can vary wildly in price depending on their backend needs.
The cost of a custom web application in 2026 depends less on the number of screens than on business complexity, integrations, data, and the expected level of reliability. Two projects with the same appearance can cost three times as much if one only needs to display information and the other must manage roles, synchronize a CRM, automate workflows, and track every action.
For an SME or a scale-up, the right question is therefore not just "how much does it cost?". It is rather: what budget should be planned to deliver a useful, secure V1 that is adopted by the teams and capable of generating a measurable return on investment?
Here are realistic ranges, the factors that cause the budget to vary, and a simple method to compare quotes without getting trapped.
The amounts below are orders of magnitude in euros excluding taxes, for a professional V1 delivered by a reliable team. They do not always include recurring costs such as hosting, licenses, AI APIs, maintenance, or post-launch evolutions.
Type of custom web application | Indicative V1 budget | Common timeframe | Example of scope |
|---|---|---|---|
Simple internal tool | €8,000 to €25,000 | 2 to 6 weeks | Business form, mini-dashboard, automation of a manual workflow |
Extranet or client portal V1 | €25,000 to €70,000 | 1 to 3 months | Secure login, roles, documents, request tracking, notifications |
Complete business application | €60,000 to €180,000 | 3 to 6 months | Specific workflow, back-office, permissions, CRM or ERP integrations |
Advanced web platform | €150,000 to €400,000+ | 6 to 12 months | SaaS, marketplace, multi-entity, billing, analytics, scalability |
Web application with integrated AI | €40,000 to €250,000+ | 2 to 8 months | RAG assistant, business chatbot, document automation, connected agents |
These ranges are not catalog prices. A highly targeted internal application can cost less than a showcase website that is heavily optimized for content and SEO. Conversely, a portal that seems simple on the user side can become expensive if it needs to connect to several internal tools, manage fine-grained business rules, and comply with strict security constraints.
If your need is more about a marketing site, a UX redesign, or a showcase website, the budgetary reasoning is different. You can compare with this guide on the cost of a website redesign in 2026 to avoid confusing a website budget with a web application budget.
The price of a custom web application is not linear. Adding a static page costs little. Adding a critical business rule, a bidirectional synchronization with a CRM, or an advanced permission system can radically change the budget.
The more specific your process is, the more you need to invest in scoping, functional design, and testing. An application that reproduces a properly structured Excel spreadsheet will be relatively simple. An application that must arbitrate statuses, calculate rights, trigger validations, and manage exceptions requires much more work.
A common trap is underestimating edge cases. For example: what happens if a request is canceled? Who can modify data after validation? How do you handle an import error? Who receives a notification if a deadline is missed? These details often weigh more heavily than the visible interface.
An application used by a single type of user costs less than a platform with administrators, managers, clients, partners, and internal teams. Each role adds access rules, adapted screens, tests, and sometimes confidentiality issues.
In an SME, a client portal may seem simple at first: login, documents, requests. But if each client sees different information, if certain actions require internal validation, and if the history must be kept, the budget automatically increases.
Integrations are one of the biggest variation factors. Connecting to HubSpot, Salesforce, Odoo, Stripe, Airtable, Notion, an ERP, or business software can be simple if the APIs are clean and well-documented. It can become complex if the data is inconsistent, if rights are poorly defined, or if the target tool has technical limitations.
It is also necessary to distinguish a read-only integration from a complete synchronization. Reading data from a CRM is generally simpler than creating, modifying, deduplicating, and synchronizing objects in both directions.
An internal application used by five people can accept a sober interface if it saves time. A client portal, a SaaS, or a marketplace must inspire trust, be fluid, responsive, accessible, and consistent with your brand.
The difference in cost does not only come from graphic design. It comes from user research, user journeys, prototypes, micro-interactions, error messages, empty states, responsiveness, and usability testing.
Authentication, session management, encryption, activity logs, backups, GDPR, access management, traceability: these elements are sometimes invisible in a demo, but essential for a professional application.
The more sensitive data the application handles, the more budget must be allocated for security, audits, testing, retention policies, access rights, and documentation.
A serious quote should not just display a global price. It must show the main work items, even if the level of detail varies depending on the collaboration model.
Budget item | Common order of magnitude | Why it matters |
|---|---|---|
Product and functional scoping | €2,000 to €15,000 | Clarify objectives, prioritize V1, avoid scope creep |
UX, user journeys, and mockups | €4,000 to €30,000 | Design a usable application, not just a developed one |
Front-end and back-end development | €15,000 to €180,000 | Build screens, business rules, APIs, database, and application logic |
Integrations and automations | €5,000 to €80,000 | Connect the application to your existing tools |
Data migration and structuring | €3,000 to €50,000 | Clean, import, transform, or synchronize data |
Testing, security, and QA | €5,000 to €40,000 | Reduce bugs, validate rights, secure the production release |
Deployment, monitoring, and documentation | €2,000 to €25,000 | Go into production with a minimum of control and maintainability |
Project management and coordination | Variable | Keep the project aligned with business objectives and trade-offs |
On a small project, several items can be grouped together. On a critical application, they must be explicitly planned. Savings made by skipping scoping or testing often reappear later in the form of delays, bugs, redesigns, or technical debt.
In 2026, many web application projects integrate an AI layer: internal assistant, smart search, document generation, automatic analysis, chatbot, summarization, classification, or an agent connected to business tools.
AI is not limited to the cost of an API. The budget depends mainly on the context to be provided to the model, guardrails, evaluation, observability, and integration into the workflow.
AI feature | Indicative additional budget | Points of vigilance |
|---|---|---|
Simple assistant connected to a few rules | €5,000 to €25,000 | Prompt quality, UX, clear limits |
Chatbot or RAG assistant on internal documents | €15,000 to €70,000 | Source quality, citations, access rights, anti-hallucination tests |
Document automation | €20,000 to €100,000 | Document formats, human validation, reliable extraction |
AI agent acting within business tools | €40,000 to €150,000+ | Permissions, logs, validation thresholds, reversibility of actions |
AI becomes profitable when it reduces a recurring cost, accelerates a process, or improves a conversion. It becomes dangerous when added as a demo feature without KPIs, guardrails, or a business owner.
The following examples are intentionally simplified. They provide an order of magnitude, not a replacement for a quote.
Scope: client login, document space, request submission, status tracking, email notifications, simple internal back-office.
Probable budget: €35,000 to €80,000 excl. tax for a V1. The project can be delivered in 6 to 12 weeks if the business rules are clear and the data to be displayed is accessible.
Costs increase if the portal must manage multiple entities, complex rights, synchronization with a CRM or ERP, or advanced validation workflows.
Scope: replacement of a process operated in Excel and Slack, internal roles, dashboard, statuses, automations, CRM integration, exports, action history.
Probable budget: €80,000 to €180,000 excl. tax. This type of application often creates value by reducing errors, double data entry, processing times, and dependence on a few key people.
The priority should be to deliver a complete end-to-end workflow rather than a too-broad set of incomplete features.
Scope: user accounts, subscriptions, multi-client management, back-office, billing, onboarding, analytics, support, security, monitoring, and scalability.
Probable budget: €150,000 to €400,000 excl. tax for a serious first version. The amount can exceed this range if the product targets a demanding market, a high level of scalability, numerous integrations, or an advanced AI layer.
In this case, the development budget is only part of the investment. You must also plan for acquisition, support, maintenance, product evolution, and continuous improvement.
The Total Cost of Ownership, or TCO, is often more useful than the development price alone. A web application is not a static deliverable. It lives, evolves, sometimes encounters errors, must be updated, monitored, and improved.
A simple formula:
12-month TCO = initial development budget + hosting + licenses + API costs + maintenance + support + evolutions + training and adoption.
Recurring cost | To be planned from the start | How to estimate it |
|---|---|---|
Hosting and infrastructure | Yes | Based on traffic, database, storage, criticality |
Third-party licenses | Yes | CRM, payment, email, analytics, monitoring, AI tools |
AI APIs and variable usage | If AI is integrated | Based on request volume, context size, models used |
Corrective maintenance | Yes | Often 10 to 25% of the initial budget per year depending on criticality |
Product evolutions | Yes | Quarterly roadmap, user feedback, new integrations |
Support and training | Yes | Documentation, onboarding, assistance, change management |
A very low quote can become expensive if nothing is planned for the run phase. Conversely, a higher quote can be more profitable if it includes a maintainable architecture, clear documentation, testing, and a regular delivery method.
Reducing the price is not about negotiating every line downwards. Above all, it is about reducing uncertainty, prioritizing the right scope, and avoiding developing what is not differentiating.
The most effective levers are simple:
Start with a vertical V1, with a complete but limited workflow.
Reuse existing building blocks for authentication, emails, payments, or analytics.
Limit the number of integrations in V1 to truly essential tools.
Decide early on what falls under SaaS, no-code, automation, or true custom development.
Write clear acceptance criteria to avoid vague back-and-forths.
Involve pilot users from the very first mockups.
Measure a business KPI right from launch, such as time saved, error rate, or volume processed.
The best V1 is not the smallest possible. It is the smallest version capable of proving real business value.
Comparing two quotes solely on the total price is risky. One might include scoping, testing, integrations, and deployment. The other might be limited to visible development, with many topics left out of scope.
Element to check | What to look for in the quote |
|---|---|
Functional scope | Clear list of included and excluded workflows |
Assumptions | Connected tools, data quality, roles, volumes, constraints |
Deliverables | Mockups, application, documentation, access, code, production environment |
Delivery method | Regular demos, QA, prioritization, trade-offs |
Ownership and reversibility | Access to code, documentation, cloud accounts, dependencies |
Security | Authentication, rights, logs, backups, secrets management |
Maintenance | What is included after delivery, fix turnaround times, support |
Evolutions | Terms for adding new features |
A good service provider should be able to explain why a certain feature is expensive, which assumptions can cause the budget to vary, and what options allow reducing the scope without breaking the value.
A custom web application is not always necessary. If your need is standard, not very differentiating, and well covered by existing software, a SaaS or a no-code solution may suffice.
Custom development becomes relevant when your process is specific, your tools do not communicate properly, the user experience is strategic, the data is sensitive, or the automation must follow business rules unique to your organization.
In practice, many good projects are hybrid: an off-the-shelf CRM for customer relations, an existing payment tool, a well-structured database, and then a custom web layer to orchestrate the workflow that truly makes your difference.
At Impulse Lab, pricing a web or AI application starts with business value, not a list of features. The goal is to understand the process to improve, the users, the available data, the tools already in place, and the KPI that will allow judging success.
This approach allows distinguishing three things: what absolutely must be delivered in V1, what can be automated with existing building blocks, and what deserves custom development. It is particularly useful for SMEs and scale-ups that want to structure their operations without launching an endless project.
Impulse Lab supports companies with AI opportunity audits, the development of web and AI platforms, process automation, integration with existing tools, and training teams for adoption.
What is the minimum price of a custom web application in 2026? For a very simple V1, the budget can start around €8,000 to €25,000 excl. tax. Below that, it is often a prototype, a no-code tool, a very limited scope, or a project that postpones certain costs until later.
Why does a web application cost more than a website? A website mainly presents content. An application manages users, data, rights, workflows, actions, integrations, and sometimes stricter security obligations. The cost comes mostly from this invisible business logic.
How much should be planned for maintenance? A prudent estimate is to plan for 10 to 25% of the initial budget per year, depending on the criticality of the application, the volume of users, external dependencies, and the desired pace of evolution.
Should you choose a freelancer or an agency? A freelancer can be relevant for a targeted and low-risk scope. An agency is often more suitable when the project combines product, UX, development, integrations, security, AI, management, and adoption support.
How do you know if the quote is too expensive? A quote is too expensive if it does not link the budget to a clear business value. It is too low if it forgets scoping, testing, security, integrations, maintenance, or documentation. The right quote makes assumptions, trade-offs, and the total cost of ownership explicit.
If you are considering a custom web application, the best first step is to scope a measurable V1 before requesting full development. This avoids vague quotes, useless features, and budget overruns.
Impulse Lab can help you audit your needs, prioritize features, estimate a realistic budget, and develop a web or AI platform adapted to your processes. The goal: transform a business need into a useful, integrated, and maintainable solution.
Our team of experts will respond promptly to understand your needs and recommend the best solution.
Got questions? We've got answers.
Leonard
Co-founder
