This study aims to design and develop a web-based information system that can support the administration and registration of computer training participants at the Computerization Development Institute. This system was developed using the System Development Life Cycle (SDLC) with an Agile model that emphasizes iterative and flexible processes so that development can adapt to user needs. During the analysis phase, requirements related to training management, participant registration, and payment validation were identified. The design phase was carried out using Unified Modeling Language (UML) modeling, including use cases, activity diagrams, sequence diagrams, and class diagrams to visually depict the system’s workflow. The system was implemented using the PHP programming language, the Bootstrap framework for the user interface, and MySQL as the database. Key features of this system include training data management, session scheduling, online participant registration, and payment validation. The system also provides administrators with ease of data management and ensures transparency for participants during the registration process. Testing was conducted using black-box testing to ensure that all functions operate as expected. The research results show that the developed system is capable of assisting the Computerization Development Institute in conducting training administration in a more structured and efficient manner, and making it accessible online according to user needs.