I keep seeing the same question from junior developers: "Which course should I buy?"

Wrong question. Some of the best computer science education on the planet is free, published by the same universities people take student loans to attend. You do not need their diploma. You need what is in their lectures, and they give that away.

Here is where to look. I filtered this down to IT and CS only, because that is what most of you are here for.

Harvard - start with CS50

If you take one thing from this post, take CS50. It is Harvard's intro to computer science and, in my opinion, the best free programming course ever made. C, Python, SQL, web basics, real problem sets that make you sweat.

Harvard also has a full free course catalog with follow-ups: CS50 variants for Python, web development and AI.

MIT - the deepest well

MIT OpenCourseWare is over 2,400 real MIT courses. Lecture videos, notes, assignments, exams. No registration, no account, nobody asking for your email.

Go here when you want depth: algorithms, data structures, math for programmers, operating systems, machine learning theory. This is not "learn to code in 30 days" content. It is the actual courses MIT students take, and they are hard. That is the point.

Stanford - machine learning and databases

Stanford lists its free courses at online.stanford.edu/free-courses. The strong areas are machine learning, AI and databases. Modern ML education basically grew out of material that started here, so if AI is your direction, this is a natural stop.

Cambridge - distributed systems, straight from the lecture hall

Two things worth your time:

  • Cambridge publishes its undergraduate distributed systems lectures free on YouTube, taught by Martin Kleppmann, the author of Designing Data-Intensive Applications. If you work with backend systems, you will meet this material in interviews sooner or later.
  • On edX, Cambridge partners with Arm on embedded systems and IoT courses, free to audit.

Yale - one for the money side

Yale is not an IT school online, but Open Yale Courses has Robert Shiller's Financial Markets, filmed lecture by lecture. If you are a developer heading toward fintech, watch it. Understanding what your code moves around is a real advantage over developers who only know the code.

What about Oxford?

People keep sharing "free Oxford courses" lists. I checked. Their free edX offering is almost entirely business, finance and leadership. Nothing wrong with that, but if you came here for IT, skip it.

How "free" works here

Two models, so you know what you are getting:

  1. Audit track (edX, Harvard catalog) - all the content is free, you only pay if you want a certificate.
  2. Open courseware (MIT OCW, Open Yale, Cambridge YouTube lectures) - everything is free and there is no certificate at all.

And here is my honest take on the certificate question: in 200+ interviews, I have never once hired someone because of an audit-track certificate. I have hired people because of what they built. Take the free version, build a project with what you learned, put that in your portfolio. That is the paper that matters.

Pick one course. Finish it. Most people bookmark posts like this and never open a single lecture. Do not be most people.