The self-assessment system was developed based on the assessment as learning (AaL) approach, in which learners take responsibility for their own learning and use feedback for self-intervention. The feedback as the system's principal component was produced using assessment data in the system. It is essential for the assessment as learning that students construct their interventions to their learning processes by using assessment feedback. From this point, this study aimed to evaluate the web-based self-assessment system through the lens of student perceived self-intervention. The one-shot case study design (one-group post-test) model, one of weak experimental design, was used as a research design. The web-based self-assessment system was employed over a 10-week period to support face-to-face lessons. At the beginning of the implementation process, students taking the "Measurement and Evaluation in Education" lesson in the education faculty were informed about the system. After the implementation process, the perceived self-intervention scale was used to determine the students' perception. A total of 214 students (71%) took at least one test in the system and gained access to the feedback module. The high level of participation in a non-mandatory system may be considered a success. Learners appeared to have utilized feedback gained from the system in planning self-intervention and monitoring and evaluating the planned intervention's effectiveness.