Twenty-first-century learning requires students to develop independent learning skills and effectively utilize technology as a learning resource. In learning quadratic functions, students often experience difficulties in understanding the relationship between algebraic forms and graphical representations. Therefore, a learning medium that supports concept visualization and independent learning is needed. This study aimed to develop an interactive website with a coefficient randomization feature that meets the criteria of feasibility and practicality while supporting students' independent learning in quadratic function learning. This study employed a Research and Development (R&D) approach using the 4D model, which consists of the Define, Design, Develop, and Disseminate stages. The research subjects included expert validators, a mathematics teacher, eleventh-grade students as respondents for the media practicality test, and class X-H students of MAN 1 Mataram as the implementation subjects. The research instruments consisted of a media feasibility assessment sheet, a media practicality questionnaire, and a students' independent learning questionnaire. Data were analyzed using descriptive quantitative analysis. The results showed that the developed website achieved a feasibility score of 97.71% (very feasible), a practicality score of 93.53% (very practical), and an increase in students' independent learning from 64.69% to 88.67%. Therefore, the interactive website with a coefficient randomization feature met the criteria of being highly feasible and highly practical and can be used as a learning medium to support students' independent learning in quadratic function learning.