Development
Custom web application development
A web application is software accessed from a browser, with no installation, that lets your users view, enter and process data: customer portal, internal management tool, back office, dashboard, partner area. Unlike a brochure site, it relies on user accounts, access rights and business logic.
Agencei builds web applications for companies whose processes no longer fit in spreadsheets or generic tools: request management, case tracking, scheduling, internal invoicing, reporting. We also build customer or partner portals on top of an existing system.
We build these applications with React and Next.js on the front end, Node.js or Spring Boot on the server side, backed by a relational database and authentication suited to your organization.
When do we step in?
Moving away from spreadsheet-based management
Your processes rely on shared files, multiple copies and data entry errors. A web application centralizes data, enforces business rules and tracks changes.
Opening a customer or partner portal
Your customers call to check order status, download a document or submit a request. A secure portal gives them self-service access and relieves your teams.
Building a management back office
Your product or business needs an administration interface: user management, content approval, operations tracking, exports.
Replacing an ageing internal tool
The application built years ago only runs on an old browser and nobody dares touch it. We rebuild it progressively without interrupting operations.
Creating a business dashboard
Your data is scattered across several systems. A dedicated application aggregates it, presents it clearly and supports decisions with up-to-date figures.
How we work
- 1
Process analysis
We document current workflows, roles, business rules and the data involved, meeting the people who will use the tool every day.
- 2
Functional design and mockups
Data modelling, screen breakdown, mockups of the main journeys, validation with key users.
- 3
Architecture and technical foundations
Stack selection (React or Next.js, Node.js or Spring Boot, PostgreSQL), setup of authentication, permissions, deployment pipeline and environments.
- 4
Iterative development
Usable features delivered every two to three weeks, regular demos, adjustments based on feedback.
- 5
Testing, data migration and rollout
Automated tests and user acceptance, import of existing data, training, gradual production rollout.
- 6
Evolution and maintenance
Fixes, security updates and new features at the pace of your business.
Technologies we use
- React
- Next.js
- TypeScript
- Node.js
- NestJS
- Spring Boot
- PostgreSQL
- Prisma
- Keycloak
- Docker
- AWS
- GitLab CI
Related expertise
Why choose Agencei?
Understanding the business before writing code
We spend time with your users to understand edge cases and exceptions, which make the difference between a tool that is adopted and one that is worked around.
Consistent front end and backend
Our teams cover React, Node.js and Spring Boot: API contracts, permission handling and performance are designed as one.
Frequent, verifiable deliveries
You see the application working early and often, so course corrections happen before gaps become expensive.
Security built in
Robust authentication, role management, logging, protection against common web vulnerabilities: these topics are handled from the architecture stage.
In brief
- What is this service?
- Custom web application development service: internal management tools, customer and partner portals, back offices and dashboards, built with React, Next.js, Node.js and Spring Boot.
- Who is it for?
- Companies and organizations whose processes can no longer be managed with spreadsheets or generic tools, or that want to give customers and partners online access.
- What problem does it solve?
- Centralizing data, making processes reliable and giving secure access to the right people, without depending on shared files or double entry.
- How long does it usually take?
- From a few weeks for a focused tool to several months for an application covering several processes and connected to existing systems.
- What factors influence the price?
- Number of processes and screens, complexity of business rules and permissions, ERP or CRM integrations, migration of existing data and security requirements.
- How does the engagement run?
- Process analysis with users, mockups, architecture setup, iterative development with demos, testing and data migration, rollout and then evolution.
- What are the risks?
- Scope growing without prioritization, misunderstood business rules, low adoption if users are not involved, underestimated integrations.
- What alternatives exist?
- Off-the-shelf software or a low-code platform if your processes are standard, an extension of your ERP if the need is close to it.
Frequently asked questions
What is the difference between a web application and a website?
A website publishes information to visitors. A web application lets identified users manipulate data and run processes: create a case, approve a step, generate a document. It requires an architecture, a database and permission management.
How long does web application development take?
A usable first version generally takes a few weeks to a few months, depending on the number of processes covered and the integrations with your systems. We deliver in stages so you can use the tool before the project ends.
Why not use an off-the-shelf tool?
When existing software covers your need at a reasonable cost, we tell you. Custom development is justified when your processes are specific, when market tools force workarounds or when the application becomes a competitive advantage.
Will the application work on mobile?
Yes, interfaces are designed to adapt to phone and tablet screens. If you need native features or offline use, we assess a complementary mobile app.
Can you connect the application to our ERP or CRM?
Yes. We integrate existing systems through their APIs, scheduled exports or connectors, making sure the application remains the source of truth for the data it manages.
Who owns the source code?
You do. The code is hosted in a repository in your name, documented, with the deployment pipeline needed for another team to take it over.
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See this serviceTell us about your project
Describe your need in a few lines: we come back to you with a first analysis and the next steps.