Low-cost connectivity microprocessors have enabled ordinary electronic devices to be smarter with internet-connected capabilities. Synergized with smartphones and cloud computing, smart devices have formed the internet of things (IoT), which consists of a wide range of hardware, mobile apps, and cloud services.

This diversity in smart systems offers great choices to the end-users. Yet, the same variousness generates new problems for developers: a huge amount of time is required to develop mobile applications and cloud services. Worse yet, this challenge exacerbates when applications need to be maintained or integrated with the third-party service.

This project explores the state-of-the-art of Cross-Platform Technologies (CPT), i.e., React Native, Flutter, Xamarin, and Qt: frameworks that have potential in alleviating the above issues. Another purpose of this project is to study the IoT protocols and architectures and how they can interface with CPT frameworks. Finally, this project aims to find the good designs that empowers engineers to build excellent smart systems while limiting the maintenance efforts.

In this project, information has been gathered from different sources such as official documentation, research papers, review articles, and actual experiments. The study shows that a solid cross-platform smart system should consist of four basic components: devices, gateways, engine controller, and user-space applications. The combination of lightweight IoT protocols such as MQTT, heavy-protocol like HTTP, and cross-platform mobile software empower the system to work seamlessly and smartly

As a result of this final year project, a prototype of the smart garden eco-system has been implemented at Lien Tam Buddhist Monastery in Turku, Finland. The system will be developed further in the future as an open-source project.