How we made anglers happy with a mobile app | Perpetuum Mobile

How we made anglers happy with a mobile app

Perpetuum has developed a mobile app that tracks the water levels of rivers in Croatia. The Vodostaji app warns of possible high-water hazards, enables more effective preparation for possible floods, and organizes better intervention in cases of emergency. It is also useful for a wide range of activities, including fishing, boating, and hiking.


To design and develop a mobile application that quickly, effectively, and in a timely fashion warns the user about changes in the water level of Croatian rivers, no matter where he or she is located. In addition, the Vodostaji app enables users to choose the gauge stations that they want to track, receive status messages, and have an overview of the water level and streamflow measured at a specific gauge stations over time as well as graphic representations of changes in the water level.

Business rationale

For years, Croatia has had an official information system for the collection and monitoring of hydrological data in real time. Primarily, its function is to monitor water levels, but the system also collects other hydrological (streamflow, water temperature) and meteorological (precipitation, air temperature, snow level) data. The measurements are collected in real time by automatic notification from gauge stations and stored in a database for further processing and the generation of reports and graphic representations according to the needs of end users.

Some information from the system is available to the public at the websites and Because there is a need for users to have simple access via their mobile devices, with the possibility of selecting the stations that interest them and receiving notifications in case of rising water levels, a decision was made to create native mobile apps for Android and iOS platforms. Every one of Croatia's approximately 500 gauge stations are covered by the app. The information provided by the Vodostaji app is especially useful for people who live in areas prone to flooding, but also to people who fish and anyone else who is interested in the water levels of Croatia’s rivers.

How we made anglers happy with a mobile app


Technical description

The user interface of the app was made completely in Vector graphics using the Sketch user interface design tool, with final touches made in Adobe Photoshop.

For its backend platform, the app uses the Croatian water-level service; a service for PUSH notification user preference, sending, and saving; and Google’s Firebase Cloud Messaging service. Created on the DOT.NET platform, the water-level service is the central point for the distribution of data about water levels, streamflow, and other information collected at gauge stations. At the same time, the user preference service, designed in PHP/Laravel, memorizes the gauge stations that the user tracks and receives notifications about, as well as all other messages and user settings. Firebase Cloud Messaging is Google's service for sending PUSH notifications.

For designing these mobile applications, we chose the React Native platform, developed by Facebook, which is used for the creation of native mobile applications written in JavaScript. This framework is not usually used to produce web or hybrid mobile applications, but rather for true native applications. This approach is growing in popularity for the development of mobile applications; we used it also because it reduced the development time considerably because the same programming code could be used for both iOS and Android platforms. React Native has also been used for mobile application designs by big players such as Facebook, AirBnB, Tesla, and Skype.

Download the application: