The Self-reflection on Effective Learning by Fostering the use of Innovative Educational technologies (SELFIE) tool was piloted in the Republic of Serbia (hereafter Serbia) in 2017 and scaled up in early 2019. At the beginning of 2020, the European Commission's Joint Research Centre (JRC) developed a new version of SELFIE specifically focusing on Work-Based Learning (WBL) arrangements, including a questionnaire for in-company trainers who support students during their time with employers. Serbia's Ministry of Education, Science and Technological Development (MoESTD) expressed their interest in participating in the SELFIE WBL pilot study. Based on the results of the pilot in Serbia, it can be concluded that the SELFIE WBL tool was successfully tested and validated. At the national level, the SELFIE WBL tool is seen as a useful and easy-to-use education policy tool that considers all relevant stakeholders in schools and companies, namely principals, teachers, students and in-company trainers. [This report was written with Alessandro Brolpito and Ralph Hippe. For the main report, "SELFIE for Work-Based Learning Pilots in Georgia, Montenegro, Serbia and Turkey," see ED617575.]