In this talk, Courtney Leuker from Ostron, the Dutch Institute for Radio Astronomy, discusses the use of open source software in their biggest instrument, LOFAR. They utilize open source tools such as CASA core, DP3, Rattler, AO flagger, and WSClean for data processing and imaging. Courtney explains the principles behind LOFAR, the different components of the instrument, and how radio waves are observed and analyzed in radio astronomy. He also mentions future upgrades to enhance LOFAR's capabilities. Lastly, Courtney discusses the use of open source tools, improvements that can be made, and ongoing collaborations in the field of radio astronomy.