More and more public organisations and institutions grants access to their data wishing to encourage development and progress on their working field. Nevertheless, many known barriers exist that prevent efficient usage of such data. These barriers can be consolidated into two main groups: public organisation and institution barriers and data users’ barriers. In this dissertation we will focus on technical barriers of public organisations and institutions, which ensure transparent public spending in Slovenia. Visualization of public spending in Slovenia is provided by application Erar by Commission for the Prevention of Corruption. Main goal of the dissertation is to develop a new application TransAkt based on the identified usage barriers of the application Erar. TransAkt uses complementary data sources to enrich existing Erar data and offer greater informational efficiency of public spending data in Slovenia. The application was developed in software environment R and a system for clustered and structured data processing Apache Spark. In a process of preparing the application data structure we standardised four open datasets: (1) public spending data from application Erar, (2) list of subject enlisted in Slovenian Business Register, (3) list of taxable legal and natural persons and (4) Register of geographical areas. This data structure represents the foundation of the application TransAkt, which was developed with R Shiny library. Application closes some of the identified gaps of the application Erar and offers more intuitive graphical user interface and allows to conduct exploratory analysis on Slovenian public spending data.