Report cards, attendance rosters, class schedules, discipline logs, and fee statements all live in one browser-based system with RosarioSIS, an open-source student information system for K-12 schools and similar institutions. Administrators define marking periods in up to three tiers, set grade levels and daily periods, and search students by gender, grade level, schedule, absences, GPA, or class rank. The scheduler places whole classes or a single student, and runs in test mode each time a student's requests are saved, so conflicts can be resolved with the student still in front of you. Teachers keep a weighted gradebook with grade ranges, progress reports, report cards, and transcripts, take attendance electronically, and use the eligibility feature to flag who may join athletic or academic activities. Discipline logs, student billing with fees, payments, balances, and statements, food service, and accounting complete the core modules. Parents and students get their own portal, new families can register online, listings export to Excel, CSV, or XML, and charts and PDF documents support decisions and paperwork. The interface adapts to tablets and phones and is translated into a dozen languages. Add-on modules bring email, library, hostel, Jitsi Meet video rooms, and Moodle integration. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. GPL-2.0 licensed.