Harvard University
CS50's Introduction to Programming with Python
Harvard's CS50P — ten weeks from functions to OOP, with auto-graded problem sets, a unit testing week and a self-designed final project.
Beginner10+ hours
Learn Computer Science with the Computer Science tutorials and online courses.
Fundamentals age slower than everything else. Frameworks turn over every few years; what a pointer is, how memory works, why one algorithm finishes and another doesn't — that knowledge stays useful for a whole career. It's also the material most self-taught developers skip and later wish they hadn't.
Four tutorials sit here, and three of them come from two institutions. That concentration is worth knowing about before you commit.
CS50x: Introduction to Computer Science is the obvious first stop and the most demanding thing on this site. Scratch in week zero, five weeks of C, then Python, SQL, web and an AI module, with graded problem sets and a free certificate at the end. The C weeks are where people quit and also where the value is. If that's too much, CS50's Introduction to Programming with Python is the gentler Harvard course — ten weeks, autograded problem sets, a week on unit testing, and a final project you design yourself.
The Missing Semester of Your CS Education from MIT CSAIL covers what CS50 doesn't: the shell, dotfiles, debugging and profiling, Git internals, build systems, security basics. It's the fastest way to stop feeling like a tourist in your own terminal, and we'd put it second on this list for anyone who can already program.
Four entries, and the fourth is CS50's Mobile App Development with React Native — Harvard again, retired since June 2020, dated enough on the mobile side that we list it mainly for its JavaScript and React lectures. So the real computer science content here is three courses from Harvard and MIT. There's no dedicated algorithms and data structures course, nothing on operating systems, networking, databases or compilers, and nothing on discrete mathematics. For a subject this deep, that's a thin shelf.
CS50x, then Missing Semester, and be realistic about the hours — CS50 has broken more study streaks than anything else we list. When you want algorithms specifically, you'll have to go outside this site, and that's a gap we know about.
Harvard University
Harvard's CS50P — ten weeks from functions to OOP, with auto-graded problem sets, a unit testing week and a self-designed final project.
Harvard University
Harvard's React Native course with Jordan Hayashi — strong JavaScript and React lectures, but officially retired since June 2020 and badly dated on mobile.
Harvard University
Harvard's CS50x — Scratch, then five weeks of C, then Python, SQL, web and AI, with graded problem sets and a free certificate on completion.
MIT's course on the tools degrees skip — shell, dev environment, debugging, Git internals, packaging, code quality. The lecture list has changed since 2020.