The current complaint handling methods are facing inefficiency issues such as difficulties in complaint submission and complaints status tracking by citizens. Additionally, the State Legislative Assemblies (ADUN) members in Kedah, Malaysia, face difficulties in performing comprehensive analysis regarding the complaints. Thus, the AduDUN@Kedah system, a web-based platform, was developed to optimize the management of citizen complaints directed towards the ADUN. Employing the Rapid Application Development (RAD) methodology, this study started with the analysis and quick design and ended with the deployment. The study engaged a total of 33 participants to evaluate the system, which assessed the system’s usability in terms of usefulness (85%), ease of use (85.8%), learnability (84.2%) and overall satisfaction (89.2%) using a structured questionnaire. These findings underscore the system’s readiness for broader implementation, highlighting its potential to enhance the efficiency and transparency of complaint management processes within government agencies, specifically State Legislative Assemblies (DUN) in Kedah. The citizens of Kedah could direct their complaints through this system and track them more systematically and efficiently. Theoretically, this study contributes to understanding the system requirements and design models for e-complaint systems. Future work for this system development could focus on enhancing data visualization to improve user engagement and expanding the platform to all Malaysian states to establish a one-stop center for citizens to voice their complaints to their respective ADUN.