OSSU Computer Science is the Open Source Society University: a complete, free, self-taught four-year computer science curriculum built entirely from MOOCs (Coursera, edX, MIT OpenCourseWare, free YouTube lectures). If you want the structured progression of a CS degree without the tuition, this is the closest thing to it on the internet.
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OSSU: The shape of the curriculum
The README maps a four-year CS degree into a sequence of MOOCs, organized into: Intro CS (Python, then either Harvard’s CS50 or MIT’s Intro to CS & Programming), Core CS (discrete math, algorithms, data structures, theory, computer architecture, OS, networking, databases), Advanced CS (systems, software engineering, ML, cryptography, security, distributed systems), Final Project (a substantial capstone). Each course links to its free MOOC, with the paid-certificate-track optional.
The total time commitment estimate is roughly 20 hours/week for 2 years if compressed, 4 years at standard pace. The community reports people completing it in as little as 18 months full-time or as long as 5 years part-time.
The community is the actual product
The OSSU Discord has tens of thousands of active self-learners. Study groups form per-course, peer review happens for capstone projects, and the maintainers keep the curriculum current (a course is replaced within months of going stale). The README is the syllabus; the Discord is the university. If you treat OSSU as just a reading list, you miss most of the value.
What you don’t get
A degree. OSSU explicitly does not grant a credential. You get the knowledge, the capstone, the peer community, but you cannot put “OSSU CS” on a resume the way you’d put “Stanford CS.” Some courses offer paid certificates (Coursera, edX); those are individual course certificates, not a degree. Pair OSSU with a portfolio of real projects (this is what hiring managers actually look at) and the lack of a credential matters less.
How it differs from freeCodeCamp or Coding Interview University
freeCodeCamp is web-development-focused with certifications at the end. Coding Interview University is interview-prep-focused with a checklist of topics. OSSU is full-CS-curriculum-focused, with the depth and breadth of an actual undergraduate degree (theory, math, systems, architecture). They serve different goals: pick OSSU if you want the depth, fCC if you want a job quickly, CIU if you have an interview in 4 months.
OSSU Computer Science is the free four-year CS degree replacement. Commit to the full curriculum if you want depth, or skim it to fill the gaps from a bootcamp or self-taught path. Use the Discord: the community is half the value.