Learning & Knowledge

School subjects35 websites

• 33Blue1BrownVisual explanations of mathematics and related concepts.
• AABCyaEducational games organized by grade level and subject.
• BBedtime MathEveryday mathematics activities designed for families and children.
• BBetterExplainedIntuitive explanations of mathematical concepts.
• BBrilliantInteractive problem-solving courses in math, science, and computer science.
• CChemistry LibreTextsOpen chemistry textbooks, course materials, and reference content.
• EESA KidsEuropean Space Agency educational space content for children.
• EExploratoriumHands-on science activities, experiments, exhibits, and learning resources.
• FFree Kids BooksFree children's books and educational reading materials.
• GGeneration GeniusScience and math learning videos and classroom resources; free access may be limited.
• HHHMI BioInteractiveFree biology and life-science educational resources and interactives.
• HHyperPhysicsA concept-map-based reference covering major topics in physics.
• IInternational Children's Digital LibraryDigital collection of children's books from around the world.
• LLearn.GeneticsInteractive genetics and bioscience learning resources from the University of Utah.
• LLEGO EducationLesson plans and hands-on STEAM learning resources from LEGO Education.
• MMath AcademyAdaptive mathematics learning platform.
• MMath PlaygroundMath games, logic activities, and problem-solving exercises.
• MMathuaFree, open-source adaptive math learning with prerequisite-based progression, generated practice problems and spaced repetition.
• MMystery ScienceScience lessons and activities for elementary learners and teachers.
• NNASA Climate KidsChild-friendly climate, weather, earth science, and environment resources.
• NNASA Space PlaceNASA space and earth-science activities, games, and explanations for children.
• NNeuroscientifically ChallengedAccessible explanations and videos covering neuroscience fundamentals.
• NNRICHMathematics problems and enrichment activities from the University of Cambridge.
• OOxford OwlReading, mathematics, and home-learning resources for children and parents.
• PPaul's Online Math NotesFree algebra, calculus, and differential equations notes and tutorials.
• PPhET Interactive SimulationsInteractive simulations for physics, chemistry, mathematics, earth science, and biology.
• RReading BearFree phonics and early-reading learning program.
• SScience BuddiesScience-fair projects, experiments, STEM activities, and project guides.
• SSplashLearnGrade-based mathematics and reading practice with free and paid features.
• SStarfallEarly-learning activities focused on reading, phonics, mathematics, and language.
• SStoryline OnlineChildren's books read aloud by actors and performers.
• SStoryWeaverOpen multilingual digital library of children's stories.
• TThe Feynman Lectures on PhysicsOnline edition of Richard Feynman's classic physics lectures.
• TThe Physics ClassroomTutorials, interactives, and resources for learning physics.
• UUnite for LiteracyIllustrated digital books with audio narration in multiple languages.

General knowledge34 websites

• AAeon, Editor's pickLong-form essays on philosophy, science, psychology, society, and culture.
• AArt for Kids HubStep-by-step drawing and art lessons for children and families.
• AArts & Letters DailyA daily curated selection of essays, reviews and articles on philosophy, literature, history, art and ideas, from The Chronicle of Higher Education.
• BBig ThinkIdeas, interviews, and educational content covering science, society, and culture.
• BBritannica KidsChild-focused encyclopedia and reference material.
• CCrash CourseFast-paced educational videos spanning science, history, humanities, and more.
• DData CommonsExplore interconnected public datasets about places, populations, economics, and more.
• DDK Find Out!Visual educational reference covering science, history, nature, and general knowledge.
• DDuckstersStudent-friendly explanations and reference material across school subjects.
• FFarnam StreetShane Parrish's site of articles, a weekly newsletter and a podcast on mental models, decision-making and clear thinking.
• GGapminder ToolsExplore global development data through interactive visualizations.
• GGeekNewsA Korean-language technology and startup news community with discussions, shared links and a Show section for projects.
• GGus on the GoLanguage-learning resources and apps designed for younger children.
• HHacker News, Editor's pickA technology and startup news community with reader discussions, project showcases and Show HN submissions.
• IInformation Is BeautifulExplore data visualizations that make complex topics easier to understand.
• IInternet Live StatsExplore estimates of internet activity and usage through live-style counters.
• LLearn AnythingExplore visual learning paths.
• NNASA YouTubeNASA videos, launches, space coverage, educational content, and archives.
• NNational Geographic KidsNature, science, geography, animals, and exploration content for children.
• NNautilusLong-form stories exploring science, philosophy, and culture.
• PPascal ArchitectureIllustrated explanations and interactive 3D models of buildings, structural systems and construction techniques.
• PPsyche, Editor's pickA free digital magazine of essays, guides and videos on psychology, emotions, mental health, relationships and living well, published by Aeon.
• QQuanta MagazineIn-depth journalism on mathematics, physics, biology, and computer science.
• SScienceDailyBrowse science news and research summaries across many disciplines.
• SSketchRxDrawing practice and visual-art exercises.
• SSlashdotA technology-news and discussion site covering software, open source, science and related topics.
• TTate KidsArt activities, games, and artist resources for children.
• TTED TalksTalks and explanations from researchers, experts, creators, and practitioners.
• TThe PuddingExplore visual essays and stories told through data and interactive graphics.
• WWonderopolisDaily curiosity-driven questions and explanations for children and families.
• WWorld Population ReviewExplore population statistics and country-level data.
• WWorldometerExplore continuously updated global statistics and counters.
• YYour Bias IsA free illustrated guide to 24 common cognitive biases, with plain explanations and printable Creative Commons cards and posters.
• YYour Logical Fallacy IsA free illustrated guide to common logical fallacies, explaining each flaw in reasoning with examples, plus printable Creative Commons cards and posters.

See all 37 in General knowledge3 websites are listed in an earlier section

Courses & tutorials42 websites

• KKhan Academy, Editor's pickFree lessons and exercises in mathematics, science, computing, economics, and more.
• MMIT OpenCourseWare, Editor's pickFree course materials from thousands of MIT courses.
• OOpenStaxAccess free, peer-reviewed textbooks and educational resources.
• CCourseraUniversity and industry courses, with some content available to access without a paid certificate.
• FFanoutLearning paths for AI research, system design and machine-learning mathematics.
• AAlisonOnline courses across professional, academic, and vocational subjects.
• CChrome Music LabInteractive experiments for exploring music, rhythm, sound, and composition.
• CClass Central, Editor's pickSearch and compare online courses from universities and learning platforms.
• DDisasterReadyFree humanitarian and development training for aid professionals.
• DDuolingoBite-sized, game-like language lessons covering reading, writing, listening and speaking, on the web and in iOS and Android apps.
• EedX, Editor's pickOnline courses and programs from universities and organizations around the world.
• FFAO eLearning AcademyFood, agriculture, nutrition, and rural-development learning resources.
• FFutureLearnOnline short courses and programs across a wide range of subjects.
• GGoogle SkillshopOfficial Google product training and certification resources.
• GGreat LearningProfessional and technology learning programs, including free short courses.
• HHubSpot AcademyMarketing, sales, service, and CRM training with certifications.
• IiFixit, Editor's pickRepair guides, teardowns, troubleshooting, and parts information for electronics and devices.
• IInstructables, Editor's pickCommunity archive of DIY projects, builds, repairs, crafts, and how-to guides.
• LLearnlistsA curated directory of learning websites, interactive playgrounds, courses, case studies and learning paths across programming, AI, design, mathematics and engineering.
• LLibreTextsOpen-access textbooks and learning materials across academic disciplines.
• LLinkedIn Learning, Editor's pickProfessional skills courses; access may be available through participating libraries or institutions.
• MMERLOTCurated collection of online teaching and learning materials.
• MMeta BlueprintMeta learning resources for advertising, marketing, and business tools.
• MMindLusterOnline learning platform offering free courses across technology, business, creative, and professional subjects.
• MMIT Open LearningMIT's open learning initiatives and digital education resources.
• MMusicTheory.netFree music-theory lessons, exercises, and reference tools.
• OOER CommonsDigital library of open educational resources.
• OOpen CultureDiscover free courses, lectures, books, films, and educational resources.
• OOpen Michigan, Editor's pickOpen educational resources and course materials from the University of Michigan.
• OOpen Yale Courses, Editor's pickFree recordings and materials from selected Yale courses.
• OOpenLearnFree courses and learning materials from The Open University.
• OOpenWHOWHO learning platform for health emergencies and public-health knowledge.
• SSaylor AcademyFree and open online courses across university-level subjects.
• SSemrush AcademySEO, content, advertising, and digital-marketing courses.
• SSimplilearn SkillUpFree introductory courses across technology and business topics.
• SStanford Online, Editor's pickStanford online courses and learning resources.
• TTikTok AcademyTikTok learning platform for advertising and marketing skills.
• TTU Delft OpenCourseWareOpen engineering, science, and technology course materials from TU Delft.
• UUC Berkeley OnlineOnline learning and educational resources from UC Berkeley.
• UUN CC:e-LearnUnited Nations climate-change learning platform.
• UUNHCR LearnUNHCR learning and training resources related to refugees and humanitarian work.
• UUNICEF AgoraUNICEF learning platform for staff, partners, and development practitioners.

See all 47 in Courses & tutorials5 websites are listed in an earlier section

Coding & technology learning64 websites

• CCS50 at Harvard, Editor's pickHarvard's introductory computer science course and related CS50 materials.
• TThe Odin ProjectFree open-source full-stack web-development curriculum.
• WW3SchoolsProgramming tutorials, references and interactive examples.
• 5500+ AI Agent Projects & Use Cases, Editor's pickA curated collection of AI-agent project ideas, use cases, tutorials and example implementations, organized by industry and framework.
• AAI Agents for BeginnersMicrosoft's beginner course on building AI agents, with written lessons, videos and code examples covering tool use, RAG, planning, multi-agent systems, memory, deployment and security.
• AAI Coding Dictionary, Editor's pickMatt Pocock's plain-English glossary of AI coding concepts, including models, context, agents, tools, environments, memory and workflows.
• AAI Engineering from ScratchRohit Ghumare's free, open-source course for building AI systems from first principles, implementing math, tokenizers, attention, agents, evaluation and production pieces by hand in Python, TypeScript, Rust and Julia.
• AAI Engineering NotesRatish Jain's public learning notes on AI engineering, explaining one topic at a time and linking the papers, videos and posts used to understand it.
• AAnthropic LearningCourses and learning resources from Anthropic.
• AAWS Skill BuilderAWS training resources for cloud, AI, machine learning, and related technologies.
• BBlockly GamesEducational games that introduce programming concepts through block-based coding.
• CCisco Networking AcademyNetworking, cybersecurity, programming, and IT training from Cisco.
• CCoddyInteractive programming courses with coding exercises.
• CCode.orgFree computer-science and coding lessons for students and educators.
• CCodeCombatLearn programming, including Python, by coding your way through game levels.
• CCodepipLearn HTML, CSS, JavaScript, and web-development concepts through coding games.
• CCodewarsPractice programming through community-created coding challenges and compare solutions with other developers.
• CCodinGamePractice programming across many languages through puzzles and coding challenges.
• CCybraryCybersecurity and IT training platform with free and paid learning options.
• DDeepLearning.AICourses and learning resources covering AI, machine learning, generative AI, and deep learning.
• DDevOps GamesPractice DevOps concepts through game-like challenges.
• DDistillInteractive and visual explanations of machine-learning research.
• DDive into Deep LearningInteractive deep-learning textbook with code and mathematical explanations.
• EExercismFree programming practice and mentoring across many programming languages.
• Ffast.aiPractical deep-learning courses and resources.
• FFortinet Training InstituteCybersecurity training and certification preparation from Fortinet.
• FfreeCodeCampFree coding curriculum with project-based developer certifications.
• GGenAI AgentsLearn agent patterns including tool use, planning, RAG agents, memory, multi-agent systems, and workflows.
• GGoogle AI LearningAI learning resources and courses from Google.
• GGoogle Cloud Skills BoostGoogle Cloud hands-on learning paths, labs, and skill badges.
• GGoogle for Developers LearnOfficial Google developer tutorials, pathways, and technical learning resources.
• GGuru99, Editor's pickTechnology tutorials and learning guides.
• HHackerRankCoding practice, technical assessments, and skills verification.
• HHands-On Large Language ModelsLearn LLMs by building: embeddings, transformers, RAG, fine-tuning, semantic search, and LLM applications.
• HHour of CodeShort introductory coding activities for learners of different ages.
• HHugging Face LearnFree courses and learning materials covering the Hugging Face ecosystem.
• IIBM SkillsBuildFree learning resources covering AI, technology, professional skills, and career development.
• KK8s GamesLearn and practice Kubernetes through interactive challenges.
• KKaggle LearnShort hands-on courses for data science and machine learning.
• LLearn X in Y MinutesQuick guides to programming languages and concepts.
• LLLM CourseRoadmap covering LLM architectures, fine-tuning, quantization, RAG, agents, and deployment.
• MMade With MLLearn production ML: data, modeling, evaluation, deployment, MLOps, and production systems.
• MMeta AI ResourcesAI research, learning, and technical resources from Meta.
• MMicrosoft LearnFree training paths and modules covering AI, Azure, development, data, and Microsoft technologies.
• MMicrosoft MakeCodeBlock- and text-based coding environment for learning programming with interactive projects.
• NNand2TetrisLearn computing systems by building a computer from fundamental logic components upward.
• OOh My Git!Learn Git through an interactive game using real Git commands.
• OOpenAI AcademyLearning resources, events, and educational content from OpenAI.
• OopenSAPOpen online courses and learning resources from SAP.
• OOverAPIDeveloper cheat sheets for programming languages and technologies.
• OOverTheWireLearn Linux, command-line, networking, and security through wargames.
• PpicoCTFLearn cybersecurity through capture-the-flag challenges and puzzles.
• PProjectLearnLearn programming through guided projects and tutorials.
• PPrompt Engineering GuideResources covering prompting techniques, RAG, agents, LLM research, capabilities, and optimization.
• Rroadmap.sh, Editor's pickCommunity-created learning roadmaps for developers and technical roles.
• SScratchLearn programming fundamentals through visual block-based coding and projects.
• SSololearnMobile-friendly interactive coding lessons across multiple languages.
• TTeach Yourself Computer ScienceA self-study curriculum covering core computer science subjects.
• TTechnical Engineering Articles, Editor's pickA categorized index of technical articles on X covering system design, backend engineering, distributed systems, databases, DevOps, microservices and AI engineering.
• TThe Book of ShadersAn online introduction to fragment shaders covering shader basics, mathematical drawing, patterns, randomness and noise.
• TTryHackMeHands-on cybersecurity learning through guided labs and challenges.
• TTypingClubTyping lessons and keyboard-skills practice.
• WWeb Dev for BeginnersMicrosoft's project-based introductory web-development curriculum.
• Wweb.dev LearnModern web-development courses and guides from Google.

Books, libraries & research42 websites

• PProject GutenbergAccess tens of thousands of free public-domain ebooks.
• AarXivOpen repository of research preprints across science, mathematics, computing, and related fields.
• BBiodiversity Heritage LibraryExplore digitized biodiversity literature and historic natural-history books.
• CConnected PapersVisually explore relationships between academic papers.
• CConsensusSearch scientific research and explore evidence-backed answers.
• CCooper Hewitt CollectionExplore the Cooper Hewitt Smithsonian Design Museum collection online.
• DDavid Rumsey Map CollectionExplore a large digitized collection of historical maps.
• DDigital Public Library of AmericaSearch digital collections from libraries, archives, and museums across the United States.
• DDigitalNZSearch New Zealand digital heritage and cultural collections.
• DDOAJSearch the Directory of Open Access Journals.
• EElicitAI-assisted research and literature review.
• EEuropeanaExplore digitized European cultural heritage.
• FFive BooksInterviews in which experts each recommend and discuss the five best books on a specific subject, across thousands of topics.
• FFlorence Griswold MuseumExplore American art, exhibitions, and museum collections.
• GGoogle Arts & CultureExplore museums, artworks, cultural sites, stories, and virtual exhibitions.
• IInternet ArchiveExplore archived websites, books, media, and other digital collections.
• IInternet Encyclopedia of PhilosophyPeer-reviewed reference articles on philosophers and philosophical topics.
• LLibrary GenesisSearch for books and academic materials.
• LLibrary of CongressExplore digitized books, photographs, recordings, maps, manuscripts, and historical collections.
• LLibriVoxVolunteer-read audiobooks of public-domain works.
• LLoyal BooksFree public-domain audiobooks and ebooks.
• OOnline Etymology DictionaryDouglas Harper's free dictionary of English word origins, tracing how words and phrases developed and changed meaning over time.
• OOpen LibraryExplore a digital library and borrow available books online.
• OOur World in DataExplore research and data on global health, population, energy, poverty, technology, and more.
• PPDF Drive, Editor's pickSearch for downloadable PDF books and documents.
• PPhilosophizeIntroductory philosophy resources.
• RRijksmuseumExplore the Rijksmuseum's art collection and digital resources.
• SSci-HubSearch for research papers.
• SSciSpaceFind, understand, and work with academic research papers.
• SSemantic ScholarAcademic search engine for scientific literature.
• SSmithsonian Open AccessExplore millions of Smithsonian digital items and open-access assets.
• SStandard EbooksA volunteer-driven project producing carefully formatted, open-source editions of public-domain ebooks, free of cost and of U.S. copyright restrictions.
• SStanford Encyclopedia of PhilosophyScholarly reference articles covering philosophy and related fields.
• TThe Metropolitan Museum of ArtExplore the Met's collection, exhibitions, research, and open-access artworks.
• TThe Public Domain ReviewExplore curious and remarkable works from the history of art, literature, and ideas.
• TTroveExplore Australian newspapers, books, images, archives, and cultural collections.
• UUbuWebAvant-garde and experimental art, film, sound, and writing archive.
• UUnpaywallFind freely accessible versions of research papers.
• WWikiArtBrowse a large online collection of visual art organized by artist, style, and movement.
• WWikipedia Random ArticleJump to a random Wikipedia article.
• WWorld Bank Open DataExplore global development indicators and World Bank datasets.
• ZZ-LibraryA large online library of e-books and articles. Many works are shared without the rights holders' permission, and its web addresses change often.

Study tools6 websites

• GGizmoTurn study materials into flashcards and AI quizzes.
• DDesmosInteractive graphing and mathematics tools.
• GGeoGebraInteractive tools for geometry, algebra, calculus, statistics, and more.
• GGoScholar AIAn AI service for international students to find best-fit US universities and fully funded Master's and PhD programs worldwide, and to prepare stronger applications.
• WWolfram|AlphaComputational engine for mathematics, science, data, and more.
• YYouLearnAI learning tool for summarizing and studying videos and other content.