This research aims to develop a STEAM-based e-module containing critical and independent reasoning characters. The method used in this study is Research and Development (R&D). The validation of e-modules is assessed based on three aspects, including aspects of content, construction, and language. The experts who validated each aspect consisted of four experts: three lecturers and one fifth-grade teacher. The practicality test was carried out at Supriyadi Elementary School Semarang Indonesia on 15 students and five teachers. The results of Prisma e-module validation based on content aspects were declared "valid" with a V Aiken value of 0.9615, it is declared "valid" with a value of V Aiken 0.9469 in constructed aspect, and the language aspect is declared "valid" with a value of V Aiken 0.9219. Overall, aspects of Prisma's e-module were declared "valid" with an Aiken V value of 0.942. Prisma's e-module received a practicality test score of 86% from students and 96% from educators. It can be concluded that Prisma's e-module is declared "feasible" and "practical" for use in the learning process. Further research can develop e-modules that can be accessed not only in the Android program but also accessible in the iOS program.