A web application is a program that runs in a web browser and in which the user gets work done: they sign in, enter and change data, approve, order or track a status. It does not need to be installed, it works on a computer, tablet and phone, and all users work on the same, current version. When users need to work without an internet connection or need access to the camera and location, a mobile app may be the better choice.
Website or web application
A website presents a company: a visitor reads about its services and gets in touch through a form. A web application is for getting work done: the user has their own account, sees their own data and changes it within the limits of their permissions. The difference is not in how it looks but in what happens behind the screen: an application has a database, business rules, user roles and connections to other systems, so building one is a different job too. An online shop is a special kind of web application, made for selling, and we describe how we build one on our online shop development page.
When you need a web application
A web application makes sense when several people, inside and outside the company, have to work with the same data and spreadsheets and email can no longer keep up. These are the typical cases.
Client portals
A place where customers see their orders, contracts, invoices, documents or the status of a request, and start for themselves whatever they would otherwise phone or email about.
Business partner portals
For wholesale customers, distributors, suppliers or service partners: terms and price lists per partner, orders, complaints and documentation, with each partner seeing only what concerns them.
Internal tools
Applications for employees that replace spreadsheets and email chains: work orders, request approvals, resource planning, records and the workflow between departments.
Dashboards
Key figures on one screen, calculated from data you already have in your ERP, CRM or accounting, instead of reports put together by hand. If the data first needs tidying up and connecting, see our data and business analytics page.
Each of these applications is a form of custom software. Our custom software development page explains when custom development pays off and when an off-the-shelf product is better.
Technology
We build web applications on the technologies we use in our own products and in client work: Next.js and React for the interface, Node.js for the backend and PostgreSQL for the database. When an application needs search by meaning, for example across documents or a knowledge base, we extend PostgreSQL with pgvector. We package the application with Docker, and changes pass automated checks in GitLab CI before release.
These are widely used open-source technologies, so another team can also understand the application and develop it further. The applications we build and maintain run on servers in the EU.
Security and access rights
A web application can be reached from the internet, so we plan security from the start, not as an add-on at the end:
- every user has a role that determines what they may see and change, and a partner sees only their own data;
- permissions are checked on the server with every request, not just by hiding buttons in the interface;
- the connection is encrypted, and where needed we add an extra verification step at sign-in;
- important actions are logged: who changed what and when;
- only the personal data the application needs is processed, and the data is kept on servers in the EU.
If the application uses AI, the rules for how it works and how it is overseen are described on our AI security and governance page.
Connecting to your ERP and CRM
A business web application rarely works on its own. Data on customers, products, prices and stock is usually already in the ERP or CRM, so the application reads it from there instead of someone retyping it. Depending on the system, the connection runs through an API, regular synchronisation or data exports.
For Instar informatika, a Croatian retailer and distributor of IT equipment, we connected our Business Booster platform to the Luceed ERP. The platform works on a read-only copy of the data that is synchronised every night, so work in the ERP is left untouched. That copy is the basis for weekly sales and stock reports by brand and for answers to business questions asked in Croatian. What an ERP connection looks like when it includes AI is described on our AI integration with CRM and ERP systems page.
How we build a web application
We run web application development in phases, so that users work in the real application as soon as possible:
- A free first call: who will use the application and what work they will do in it.
- Discovery: roles, permissions, screens, business rules and the systems the application connects to. Where it helps, we sketch the main screens before development.
- Scope, cost estimate and a phased plan.
- A first working version in 4–8 weeks, with real sign-in, roles and your data. You follow progress in the client portal.
- Onboarding users, improvements based on their feedback, and the next phases.
- Maintenance after go-live.
What the price depends on
The cost estimate is affected by:
- the number of user types and how finely their permissions are defined;
- the number of screens and the complexity of the business rules;
- integrations with your ERP, CRM, payment system or email, and what kind of API those systems have;
- migrating existing data;
- the look: ready-made interface components or a custom design based on your visual identity;
- the number of interface languages, and the reports and exports you need;
- the scope of maintenance.
We give the estimate after discovery, split by phase, so you know in advance what goes into the first version.
Maintenance
A web application is not finished when it goes live. Browsers, libraries and security requirements change, and over time users ask for improvements. Maintenance covers updates and security patches, monitoring, database backups and bug fixes, while larger changes are planned as new phases with their own estimate.
What to prepare
To get started, it helps to have:
- a list of users: who signs in and what each group may see;
- examples of the spreadsheets, forms and reports the application replaces;
- the API documentation for your ERP or CRM, or a contact for the person who maintains it;
- your visual identity, if customers and partners use the application;
- a person who decides on priorities, and a few users for testing.