Open Source Society University: Computer Science

What it is

Open Source Society University (OSSU) publishes a full computer science curriculum modelled on undergraduate degree requirements, using courses from universities such as MIT, Princeton and Stanford, offered online. It is one of the most starred education repositories on GitHub, with about 209k stars and 26k forks as of September 2026, and it is still actively maintained.

The curriculum has four phases:

1. Intro CS: a single introductory course to test whether computer science is for you. The README estimates about 14 weeks at 6 to 10 hours a week.
2. Core CS: the required material, in eight areas: programming (systematic design, object-oriented and functional programming across several languages), mathematics (calculus and discrete maths), CS tools (command line and version control), systems (architecture, operating systems, networking), theory (algorithms and data structures), security, applications (databases, machine learning, graphics, software engineering) and ethics.
3. Advanced CS: electives to specialise in, such as advanced programming, systems, theory, security or maths.
4. Final project: a substantial project to consolidate what you learned.

How long it really takes

The README says it is feasible in about two years at roughly 20 hours a week. For someone studying alongside a job or degree at 10 hours a week, the same work takes around four years. Knowing this upfront matters more than anything else about OSSU.

Is it free?

The README says all or nearly all course material is free. Some courses are hosted on Coursera or edX, where graded assignments or certificates may be paid; both platforms offer financial aid, and you can usually audit the lectures for free.

What it gives you and what it does not

It gives you the syllabus, the sequencing and the materials. It cannot give you deadlines, classmates, a teacher or a degree certificate, and those are what make most people finish university. The community's Discord server, with channels for individual courses, is the closest substitute: people form study groups, ask for help and hold each other accountable.

How people succeed with it

• Treat it as a multi-year commitment with a weekly schedule, not something to dip into.
• Join or form a study group on Discord for each course.
• Keep a public log or repository of your progress and solutions.
• Do not skip the maths or the problem sets; they are where the degree-level understanding comes from.
• Build projects alongside, so you have a portfolio as well as knowledge.

Common questions

Will employers accept it instead of a degree? It is not a credential. What it gives you is knowledge that shows in interviews and projects. In markets where a degree is a hard filter, it will not replace one.

I am already a CS student. Is it useful? Yes, as a map of what a good curriculum covers and a source of better courses for subjects your university teaches weakly.

OSSU or Teach Yourself CS? OSSU is a complete, course-based curriculum. Teach Yourself CS is a shorter, book-based list of nine subjects for people who already program. Pick OSSU if you want the full degree structure.

Best for: highly self-directed learners who want a complete computer science education for free and have years, not months, to give it.