The Open Source Society University Computer Science repository is a comprehensive, free curriculum designed to provide a complete self-taught education in computer science equivalent to an undergraduate degree program. Hosted at cs.ossu.dev with its primary codebase in HTML, the project serves learners worldwide who seek a rigorous, well-rounded foundation in computing fundamentals without the cost of traditional higher education.
The curriculum is structured around four main progression levels. Intro CS introduces students to programming and computational thinking through a single foundational course. Core CS comprises required coursework spanning five major areas: core programming covering functional and object-oriented design patterns, core mathematics, CS tools, core systems, core theory, core security, core applications, and core ethics. Advanced CS offers elective specializations allowing students to develop expertise in areas like advanced programming, systems, theory, information security, and mathematics. The Final Project stage requires students to validate and consolidate their knowledge through a peer-evaluated capstone project.
The curriculum design explicitly follows the CS 2013 Curriculum Guidelines for Undergraduate Degree Programs in Computer Science, with course selection criteria requiring that all materials be openly enrollable, run regularly in self-paced or frequent formats, maintain high pedagogical quality, and come from institutions like Harvard, Princeton, and MIT. When suitable courses are unavailable, the curriculum supplements with textbooks. Additional high-quality materials that don't fit the core structure are organized in extras sections for courses and readings.
The project maintains active community engagement through a Discord server where students introduce themselves and collaborate, with GitHub issues serving as the primary venue for curriculum improvements and course-related discussions. The repository has demonstrated steady growth, with stargazer counts increasing from 205,902 to 205,906 and forks growing from 25,569 to 25,570 between tracking periods. The project includes a code of conduct and contribution guidelines to maintain community standards.
Practical support tools include a Google Sheets timeline calculator allowing students to estimate completion dates based on their available study hours per week, typically requiring about two years at twenty hours weekly. The curriculum explicitly addresses cost transparency, noting that most materials are free though some courses charge for graded assignments, with both Coursera and edX offering financial aid options. Students are encouraged to work through courses in recommended order, though flexibility exists for those with prior knowledge or those studying multiple courses simultaneously.
The repository includes clear warnings about outdated third-party materials, directing users exclusively to the official GitHub repository and website to avoid deprecated Firebase apps, Trello boards, and unmaintained Notion templates. Prerequisites are clearly specified, with Core CS assuming high school mathematics completion and Advanced CS requiring completion of all Core CS coursework plus basic physics for systems-focused tracks. The project emphasizes that success cannot be purchased, positioning discipline, will, and good study habits as essential factors for completion.
