Abstract
Assessment instruments that are inauthentic and have not been able to measure 21st century skills are the main problem with the lack of optimal assessment as a measuring tool for learning outcomes. In addition, the learning process that is not based on high-level thinking makes the learning outcomes obtained are not optimal. One of the innovations in dealing with these problems is to develop authentic assessments based on digital literacy integrated worksheets that can assist educators in measuring learning outcomes, authentic learning guides, and improve students' 21st century skills. The product was developed referring to the ADDIE development model with Aiken's V data analysis techniques to measure instrument and product validation, Alpha formula, and coefficient of agreement to measure the reliability of assessment instruments. The results of instrument and product validation are included in the valid category. While the results of the reliability assessment of knowledge and attitudes are included in the reliable category, so that the assessment can be trusted to measure student learning outcomes. Based on the results of the 21st century skills analysis, it was found that the critical thinking and problem solving skills of students were included in the not high category. Meanwhile, collaboration skills and communication skills are included in the fairly high category. so it can be concluded that authentic assessment based on digital literacy integrated worksheets can be used to assess the 21st century skills of students.