Mobile apps
An app built for iOS and Android.
Thinking about having an app built for iOS and Android? An app is rarely just an app. User management, APIs, publication in the app stores, monitoring and the next version of both operating systems: we build those into the project from the start, because it pays off in the long run.
No users, budget or post-launch plan yet? Then we first check whether an app is the right step at all.
When is a mobile app the right fit?
A mobile app makes sense when people use it regularly, work on the road or on site, or need features such as camera, push notifications, NFC, Bluetooth and offline use. Zenjoy has been building apps from Leuven for fifteen years, for both platforms, as part of a larger product: with backend, data, publication and App Care. Not a campaign app that goes quiet after three months.
Three products, not three demos
S.Tool — an app for patients and researchers
For KU Leuven and UZ Leuven, we built an app in which patients track bowel symptoms, in Dutch, French and English. Researchers manage their studies and export the data through a separate web application.
Web + app for volunteers who prepare trips
For years, we have worked on a platform for Karavaan that helps volunteers prepare hundreds of trips. The mobile app connects to that platform and gives them access to country information while travelling, even without an internet connection.
Wearable, app and data layer for sleep diagnostics
For Ectosense, we worked on product design and software prototypes for web, mobile and wearables. This earlier digital sleep care project focused on the connection between software and hardware.
Apps that keep working in the field
Three numbers from apps that are still running today: a first version in the app stores in under three months, one product on both platforms at the same time, and an app that serves as the interface to a wearable.
When is an app actually the right form?
Fieldwork, an event, a trip, a toilet visit, a school or a construction site: a desktop is awkward there.
Without backend, data and roles, all that is left is an empty shell. We would rather build the whole.
App stores, privacy, offline use, languages and the ethics committee: that is where the real product work begins.
Operating systems and SDKs keep changing. That is why App Care is not an afterthought.
An app that only looks good is not enough. A product proves itself when people keep using it for weeks on end.
Having an app built: what exactly do we build?
Not every idea belongs in the app stores. An application pays off when people use it regularly, work on location or need device features. In other cases a mobile website does the same job, without app stores, updates and double maintenance. The table below puts the two side by side.
| An app makes sense | Probably not an app |
|---|---|
| Repeated use (members, patients, volunteers, staff) | A single campaign or event, with no follow-up |
| Device features needed: camera, push notifications, GPS, NFC, BLE or offline use | The same as the website, in a WebView |
| Integration with a platform, device or research data | No users, data or owner after launch yet |
Good use cases
- A mobile application alongside an existing web platform
- Research and digital health, with participants, logging and follow-up
- Collecting data on site, at events, on trips and offline
- Applications for hardware and wearables
- A prototype for a grant application or validation, with a clear path to production
Native or cross-platform depends on the device features, the budget and the maintenance. Together with your company or organisation we choose what the product needs, and take the consequences for App Care into account.
How does mobile app development work at Zenjoy?
More about our approachExplore
Who uses the app, how often, with which device features, and which system sits behind it? That is how we set the scope and the first version.
Design
Flows and screens for the tasks that really matter. We test the design with real users before a single line of code is written, so the app stays easy to use as features are added.
Build
In two-week sprints, for both platforms at the same time. Backend and APIs grow along; no loose front end on top of a system we do not know.
Test
During the build, people from your organisation test along on real devices. That way we catch bugs and slow screens before launch.
Publish
We handle the accounts for the App Store and Google Play, the store copy and visuals, and make sure the app gets through review.
Maintain
Operating systems and SDKs keep changing. With App Care the app, the backend and the hosting keep working, secure and up to date, well after launch.
A selection from fifteen years of apps
A good app starts with the right questions.
In a first call we go through five questions: who uses the app, how often, which device features are needed, which system sits behind it and who maintains everything? Sometimes a good mobile web platform is the better solution. We will say so too, as a partner rather than a supplier.
Questions we often get
A native app is built separately for iOS and Android and gets the most out of the device. Cross-platform (React Native, Flutter) means one codebase for both platforms: faster to build, cheaper to maintain, the same experience. A hybrid app is a website inside an app shell: fine for content, weak for camera, offline use and speed. A web app runs in the browser, without app stores.
We choose per product, not out of habit: device features, performance, budget and what it means for App Care all weigh in. Most of the time we land on cross-platform, unless heavy graphics or specific hardware justify native.
Custom. We start from your processes, your data and your brand identity, not from a template you have to squeeze your features into. That means a design of your own, a data model of your own and integrations with the systems you already use.
We do reuse what we can: one codebase for custom iOS and Android apps, and proven building blocks for login, notifications and payments. That way your budget goes to what makes your app different, not to what every app needs.
Yes. That is exactly the added value. A good app forms one whole with the data, APIs and processes behind it. It is not a loose front end on top of an unknown system.
Yes, for a grant application, the ethics committee or user research. We agree up front what will be needed afterwards for real users. Without a follow-up plan, a prototype is quickly abandoned.
Sometimes. For an app redesign, a technical refresh or plain maintenance, we first look at the code, dependencies, app store accounts, backend and documentation. Only then can we take on responsibility. App Care
The cost of having an app built depends on too many factors to name a price here. The biggest ones: the number of features and user roles, whether a backend and integrations are needed, hardware or offline operation, the number of languages, and whether the app has to pass an ethics committee or privacy review.
After a discovery phase we estimate a first version and the maintenance separately, so you know before we start what the app costs at launch and afterwards. That way you get a price without surprises, but only after a conversation. A prototype for a grant application is a smaller step than an app that is ready for real users.
From one sprint of one to two weeks for a prototype to several months for an app with a backend, user roles and publication in both app stores. The scope, integrations, testing and decision points determine the schedule.
We build in two-week sprints and include user testing and publication in the planning. Reviews by Apple and Google are not entirely within our control. We therefore schedule publication as a separate step.
Ready to have an app built?
Looking for a partner to build your app in Leuven? Tell us briefly who uses the app, whether that is staff, customers or participants, where that happens and which system needs to be right behind it. Then we will think it through with you.
You will talk to someone who thinks along on the substance. No obligation, no standard pitch.