Best Free Online Learning Resources
Free university-level courses, tutorials, and interactive lessons.
3Blue1Brown
Visual mathematics videos and interactive lessons that build genuine intuition for complex topics.
Advent of Code
An annual set of 25 daily programming puzzles released each December, solvable in any language, with a global leaderboard.
Andrej Karpathy's Neural Networks: Zero to Hero
A free video lecture series by Andrej Karpathy building neural networks from scratch in pure Python, from backpropagation fundamentals through GPT-level language models.
Animagraffs
Educational site publishing animated technical explainers on engines, aircraft, electronics, infrastructure, vehicles, watches, and other mechanical or scientific systems.
Anki
A free, open-source flashcard program using spaced-repetition algorithms to optimize memory retention for anything you want to learn long-term.
Bartosz Ciechanowski
Interactive long-form articles explaining GPS, mechanical watches, naval architecture, and physics — built with hand-coded simulations you can manipulate in real time.
Boot.dev
A backend-development learning platform teaching Go, Python, and computer science fundamentals through browser-based coding challenges.
Brilliant
Interactive courses in math, science, and computer science through problem-solving.
Build It
Minecraft build catalog with searchable structures, style collections, material lists, hacks, and community posts covering houses, farms, statues, and themed designs.
Codecademy
Interactive coding courses across dozens of languages and frameworks, with an in-browser editor so you write real code inside every lesson.
CodeCrafters
A platform where you rebuild production software from scratch — your own Redis, Git, Docker, SQLite, or HTTP server — guided by test suites that verify your implementation competes with the real thing.
Codewars
Practice programming through community-created challenges ("kata") ranked by difficulty, with the ability to see how other people solved the same problem.
Coursera Audit
University courses from top institutions — many can be audited free without a certificate, though availability varies by course.
Crafting Interpreters
Robert Nystrom's free book walking you through building two complete interpreters from scratch — a tree-walk interpreter in Java, then a bytecode VM in C — for a full programming language called Lox.
Crash Course
Free educational YouTube series covering history, science, literature, and more with engaging visuals.
CS50
Harvard University's introduction to computer science and programming, free online with full lecture videos, problem sets, and an active community.
CSS Grid Garden
A free browser game that teaches CSS Grid layout by having you write real grid properties to water garden plots — covering grid-column, grid-row, grid-area, and grid-template across 28 levels.
CS Unplugged
Teaches core computer science concepts — algorithms, binary, sorting — through physical activities and games, with no computer required.
Desmos
Browser-based graphing and scientific calculator with interactive equation visualization.
Duolingo
The most widely used language-learning app, using short gamified lessons, streaks, and spaced repetition to build vocabulary and grammar over time.
edX Open Courses
Online learning platform with auditable university courses from MIT, Harvard, and hundreds of others.
Exercism
A free platform for improving coding skills through practice exercises in over 70 programming languages, with optional human mentorship from volunteers.
Explorable Explanations
A hub of interactive articles that teach through play and simulation.
fast.ai
A practical deep learning course designed for people with coding experience who want to build and understand neural networks without requiring a math PhD first.
Flexbox Froggy
A free browser game that teaches CSS Flexbox by having you write real CSS properties to position frogs onto lily pads — covering all 24 flexbox properties across progressively harder levels.
freeCodeCamp
A free, self-paced coding curriculum covering web development, data science, and machine learning — with certifications and a large community forum.
Frontend Mentor
Real-world frontend challenges with professional Figma designs and no starter code — build the UI yourself and compare with community solutions.
Full Stack Open
Free university-level full-stack web development course from the University of Helsinki covering React, Node, GraphQL, TypeScript, and CI/CD.
Hugging Face NLP Course
A free, comprehensive course on natural language processing with transformers, covering the full Hugging Face ecosystem from tokenization through fine-tuning and deployment.
iFixit
A massive community-driven wiki providing free repair manuals and teardowns for consumer electronics, vehicles, and household appliances.
JavaScript.info
A comprehensive and modern JavaScript tutorial covering the language from fundamentals to advanced topics — prototypes, async/await, closures, generators, and the DOM — with interactive exercises throughout.
Khan Academy
Free world-class education platform covering math, science, humanities, and test prep for all ages.
Learn Anything
Topic discovery site that maps subjects to curated learning resources, helping users start from a broad interest and branch into structured study paths.
Learn Git Branching
An interactive visual sandbox that teaches Git operations by animating repository trees in real time as you type commands.
Learn X in Y Minutes
A community-written cheat sheet site covering 170+ programming languages and tools in a dense, example-heavy format — showing syntax and idioms from variable declaration to classes in a single scrollable page.
LeetCode
The standard platform for practicing coding interview problems, with thousands of algorithm challenges and company-tagged question sets.
Mathigon
Interactive, visual mathematics textbooks covering topics from fractions to chaos theory.
MDN Web Docs
Mozilla's reference documentation for HTML, CSS, and JavaScript — the resource professional web developers keep open in a tab at all times.
Missing Semester
MIT course teaching the practical CS tools that university curricula skip — shell, git, vim, and more.
MIT OpenCourseWare
Free lecture notes, exams, and videos from over 2,500 MIT courses.
Musicca
An interactive platform offering free music theory lessons, exercises, and virtual instruments designed for students, teachers, and musicians.
Nand to Tetris
Free course that takes you from basic logic gates to building a full computer and operating system.
Nature of Code
Daniel Shiffman's free online book and companion videos teaching creative coding through simulations of natural systems — physics, agents, neural networks, and evolution.
Open Culture
A curated aggregator of free cultural and educational media — online courses, audiobooks, ebooks, movies, and language lessons from major universities and cultural institutions.
OpenStax
Free, peer-reviewed college textbooks covering math, science, business, and humanities — funded by Rice University and philanthropic grants.
PaperMe
A web-based reader and UI experiment that applies a high-contrast, paper-like aesthetic to digital text and web browsing interfaces.
Patterns.dev
Free book on modern JavaScript and React design patterns — rendering strategies, performance optimization, and component architecture with interactive examples.
Paul Graham Essays
Archive of essays on startups, technology, and life by Y Combinator co-founder Paul Graham.
PDF Drive
A massive free search engine for PDF books and documents, covering everything from textbooks to novels.
PGExercises
A free PostgreSQL practice site with 80+ exercises covering joins, aggregation, subqueries, window functions, recursive queries, and date operations — running against a realistic club membership dataset.
Project Euler
A long-running series of challenging mathematical and computational problems designed to be solved with a short, efficient program.
Real Python
In-depth Python tutorials and articles that go well beyond beginner syntax into idiomatic patterns, internals, and real project walkthroughs.
Refactoring Guru
A beautifully illustrated guide to design patterns and refactoring techniques — covering all 23 Gang of Four patterns and dozens of refactoring recipes with before/after code examples in multiple languages.
RegexLearn
An interactive regex learning platform with visual pattern matching, immediate feedback as you type, and a structured curriculum from basic character classes to advanced lookaheads and backreferences.
Roadmap.sh
Community-built interactive learning roadmaps for every major developer role and technology.
Shortform
Detailed book summaries and analyses that go beyond synopsis to critically examine ideas and arguments.
SQLZoo
A free interactive SQL tutorial with real database exercises covering SELECT, JOIN, aggregation, subqueries, and window functions — runnable directly in the browser against live datasets.
Stanford Encyclopedia of Philosophy
A comprehensive, peer-reviewed online encyclopedia of philosophy maintained by Stanford University — free, authoritative, and continuously updated.
Teach Yourself CS
Opinionated self-study guide to computer science — selects the single best resource for each of nine core CS subjects and explains why.
The Feynman Lectures on Physics
The complete text of Richard Feynman's iconic undergraduate physics lectures, freely available online in a beautifully typeset HTML format.
The Linux Command Line
William Shotts' free comprehensive book on the Linux command line — covering navigation, file operations, permissions, shell scripting, processes, and system administration — available to read online in full.
The Odin Project
Free full-stack web development curriculum built around project-based learning and open-source resources.
Typing.com
Free touch typing course with structured lessons, games, and progress tracking for all skill levels.
Vim Adventures
A puzzle game that teaches Vim navigation by mapping terminal keystrokes to movement — first few levels free, full game paid.
W3Schools
A long-running reference and tutorial site covering HTML, CSS, JavaScript, SQL, and most other web technologies with interactive "try it yourself" editors.
web.dev
Google's free web development resource with courses, guides, and case studies on performance, accessibility, security, PWAs, and modern browser APIs — written by the Chrome team engineers.
Wikiversity
A Wikimedia project hosting free learning resources, courses, and research projects across all academic disciplines, editable by anyone.