Dev

Official Harvard CS50 free introduction to computer science course with lectures, problem sets, a problem IDE and an active global community. 100% free; paid cert. Best for first-year CS students.

Official annual December coding puzzle event by Eric Wastl, with two new programming puzzles every day from Dec 1–25, a global leaderboard and a friendly community. 100% free; supported by donations. Best for programmers of any level who want a fun yearly tradition to sharpen problem-solving skills.

Official site of the Python programming language, with downloads, documentation, tutorials and the official package index. 100% free to download, learn and use, supported by the Python Software Foundation. Best for all Python developers from beginner to advanced.

Free source-code editor by Microsoft with built-in debugging, Git integration and a massive extension marketplace. Free and open-source at its core; some Microsoft extensions opt into optional telemetry. Perfect for developers of any stack and any experience level.

Official The Odin Project free open full-stack web development curriculum with projects in HTML, CSS, JavaScript, Ruby on Rails and Node, all open source. 100% free. Best for self-taught web devs.

The home of open source, used to host and review code, manage issues and run CI/CD on every push. Free for public repos; Team and Enterprise plans add private features and security tools. Suited for individual developers, teams and open-source maintainers.

Official nonprofit learning platform with a full web development curriculum, certifications and a supportive community. 100% free to learn and earn verified certifications, supported by donations. Best for self-taught developers and career switchers.

Official package registry and command-line tool for JavaScript and Node.js, hosting the world's largest open-source ecosystem. 100% free for public packages; private packages and org features are paid. Essential for any modern web or Node developer.

Official community-driven reference site for HTML, CSS, JavaScript and Web API browser support, with up-to-date compatibility tables for every major browser, usage stats and a blog. 100% free, supported by sponsors. Best for any front-end developer who needs to know 'can I use it' before shipping a feature.

Official Google developer site with guidance, patterns and tools (Lighthouse, Learn) for building modern, fast, accessible, SEO-friendly websites and PWAs. 100% free; backed by Google's web platform team. Best for front-end developers and web teams who want a trusted source for web standards and performance.

Official open-source ORM and database toolkit for Node.js and TypeScript, with a type-safe query builder, migrations and Prisma Studio. 100% free open-source core; Prisma Accelerate and Prisma ORM with managed features have paid tiers. Best for TypeScript backend developers who want type-safe DB access.

Official-style, community-built aggregator that combines API docs from hundreds of frameworks in a fast, keyboard-friendly interface. 100% free, ad-light and open-source; works offline once loaded. Perfect for developers who want one tab for every reference.

Official open-source backend in a single binary — embedded SQLite, auth, file storage, real-time subscriptions and an admin UI, written in Go. 100% free, open-source, perfect for side projects and small apps. Best for indie hackers and weekend projects that need a backend in five minutes.

Official open-source self-hostable Heroku/Netlify/Vercel alternative — deploy apps, databases and static sites on your own server with Git push, automatic SSL, backups and a friendly UI. Community is 100% free; managed Coolify Cloud has a free tier and paid plans. Best for developers and teams who want PaaS-like DX on their own VPS.

Official frontend cloud platform by the makers of Next.js, offering Git-based deploys, previews, edge functions and a global CDN with zero config. Free Hobby tier for personal projects; Pro is a paid plan for teams with more bandwidth and seats. Best for Next.js, React and modern frontend teams.

Official zero-config WireGuard-based mesh VPN that connects your devices, servers and cloud resources as if they were on the same LAN, with MagicDNS and ACLs. Free for personal use up to 100 devices; paid Personal/Team/Enterprise plans add teams, SSO, audit logging and shared nodes. Best for developers, homelabbers and remote teams who want painless private networking.

Official container platform for building, sharing and running applications consistently across environments, with Docker Desktop and Hub. Free for individuals and small teams; paid plans add enterprise security, scanning and support. Suited for developers, DevOps and IT teams.

Official open-source API development ecosystem — a fast, lightweight Postman alternative for REST, GraphQL, WebSocket, MQTT and gRPC, with a clean web UI and a self-hostable backend. Free for unlimited local use; cloud workspaces and team features are paid. Great for developers who want a fast, ad-free API client.

Official free, not-for-profit coding practice platform with 70+ language tracks, thousands of exercises and free personal mentorship from experienced volunteers. 100% free, open-source, supported by donations. Best for self-taught developers and bootcamp grads who want structured practice with real human feedback.

Official front-end playground for building and showcasing HTML, CSS and JavaScript pens in the browser. Free for public pens and an editor; PRO adds private pens, asset hosting and a custom URL. Ideal for front-end devs sharing demos and learning by example.

Official classic collection of challenging mathematical and computational problems intended to be solved with a short program (typically under a minute), ordered by increasing difficulty. 100% free, requires a one-off free registration. Best for mathematically-inclined programmers who want deep, timeless problems.

Official Google Chrome Labs image compression and conversion web app supporting JPEG, PNG, WebP, AVIF, JXL and more, with side-by-side quality comparison. 100% free, runs entirely in your browser. Best for designers and developers who need to shrink images without uploading them.

CDN, DNS, security and developer platform that fronts millions of websites with a generous free plan. Free plan includes CDN, DNS and basic SSL; paid plans add WAF, advanced DDoS and Workers usage. Ideal for site owners, indie devs and small businesses.

Official OverTheWire free wargame community with multi-level SSH-based security challenges like Bandit, Natas and Narnia, run by the community. 100% free. Best for learning security through wargames.

Official Frontend Mentor free platform that gives devs real UI designs to build as practice, with a community, solution reviews and job board. Free; paid Pro. Best for frontend portfolio building.

Official open-source Firebase alternative built on Postgres, with auth, row-level security, realtime subscriptions, storage, edge functions and a dashboard. Free tier covers 500MB DB and 50k monthly auth users; paid Pro/Team/Enterprise plans add more storage, compute and support. Best for indie devs and startups who want a managed Postgres backend.

Official web platform for static sites, Jamstack apps, serverless functions and forms, with Git-based deploys and instant previews. Free tier for personal projects; Pro and Enterprise are paid plans for teams with custom domains, roles and audit logs. Ideal for frontend devs and content sites.

Official all-in-one DevSecOps platform for source code, CI/CD pipelines, issue tracking, security scanning and AI-assisted workflows, self-hosted or in the cloud. Free tier with unlimited users and 400 CI minutes; Premium and Ultimate are paid tiers with deeper security and compliance. Best for teams wanting a single platform from planning to production.

Official API platform for designing, testing, documenting and collaborating on APIs, with collections, mock servers, monitors and a public API network. Free tier with core features; paid plans unlock team collaboration and advanced monitoring. Best for backend and full-stack developers working with REST or GraphQL APIs.

Official JSON Hero free online JSON viewer and explorer that turns any JSON document into a searchable, tree-explorable view with schema inference. 100% free; paid Pro. Best for inspecting and sharing JSON.

Official human-friendly command-line HTTP client and web app for testing and debugging APIs, with JSON syntax highlighting, persistent sessions and AI Assist for natural-language requests. Free for the open-source CLI and web app; paid Pro/Teams plans add AI requests, collaboration and SSO. Best for backend developers and DevOps engineers.

Official Deno edge runtime that deploys JavaScript/TypeScript apps globally on a fast isolate-based edge, with built-in KV, queues, cron and a clean dashboard. Free tier covers generous usage; paid Pro plan adds higher limits and team features. Best for TypeScript and JS developers who want an edge-first deploy story.

Official coding interview prep platform with thousands of algorithm and data structure problems, contests and company-tagged sets. Free tier with many problems; Premium unlocks the full library, company lists and AI helpers. Best for candidates preparing for tech interviews.

Official LWN.net free weekly Linux news and paid subscription site covering the Linux kernel, free software, security and standards. Free weekly; paid sub. Best for kernel and free-software readers.

The largest Q&A community for programmers, with millions of answered questions on every language and framework. Free with light ads; voting and reputation unlock moderation privileges. Best for developers debugging a problem or learning a new API.

Official open-source backend-as-a-service platform with auth, databases, storage, functions, messaging and a dashboard, available as Docker self-host or managed cloud. Community Edition is 100% free; managed Cloud has a free tier and paid Pro plans. Great for developers who want a self-hostable BaaS without vendor lock-in.

Official Carnegie Mellon picoCTF free cybersecurity education platform with a year-round archive of CTF problems for students and beginners. 100% free. Best for students learning security.

Official open-source API client that stores collections as plain-text '.bru' files inside your repo (Git-friendly, no cloud lock-in), with a clean GUI and CLI. Free for individuals and OSS teams; paid Pro plan adds team collaboration, secret management and cloud sync. Best for API testing inside Git workflows.

Official online live editor for Mermaid, the popular markdown-like syntax for flowcharts, sequence diagrams, ERDs and Gantt charts, with instant preview, theme picker and SVG/PNG export. 100% free, runs in the browser. Best for developers and tech writers who want diagrams in markdown.

Official non-profit, community-driven Git hosting platform powered by Forgejo, with pages, CI, package registry and project boards. 100% free for public projects, ad-free, supported by donations. Best for FOSS projects, activists and developers who want a GitHub alternative without the tracking.

Official Stack Overflow public Q&A for developers and paid Stack Overflow for Teams private knowledge base with AI search, used by companies to capture internal knowledge. Free public; paid Teams. Best for engineering orgs.

Official TryHackMe gamified cybersecurity learning platform with browser-based rooms, CTF-style challenges and guided learning paths. Free tier; paid Premium. Best for beginners to security.

Official Hack The Box gamified offensive-security platform with realistic machines, challenges, pro labs and academy courses for pentesters. Free tier; paid VIP. Best for security pros and CTF fans.

Official Scrimba interactive screencast learning platform where the instructor edits the code in the video, so you can pause and run the code yourself. Free; paid Pro. Best for visual interactive learning.

Official Sourcegraph universal code search platform with batch changes, code intelligence and Cody AI assistant for big monorepos. Free tier; paid plans. Best for working in huge monorepos.

Official app platform that runs full-stack apps and databases close to users on a global edge network, using Firecracker microVMs and Docker. Free allowance covers small hobby apps; paid pay-as-you-go for machines, bandwidth and storage. Best for indie devs and startups who want low-latency global deploys.

Official cloud development platform for instant web sandboxes, prototypes, full apps and live collaboration, with built-in templates for React, Next, Vue and more. Free tier with public sandboxes; Pro is a paid plan with private sandboxes and faster VMs. Great for frontend devs, tutorials and quick prototypes.

Official KodeKloud paid DevOps, Kubernetes and Cloud learning platform with browser labs, real exam-style questions and certified courses by Mumshad. Paid; some free. Best for CKA / CKAD aspirants.

Official Linux Foundation paid training and certification catalog for Linux, Kubernetes, Cilium, Hyperledger and more, with many free intro courses. Paid; free intros. Best for cloud-native cert prep.

Official long-running tutorial reference for HTML, CSS, JavaScript, Python, SQL and more, with try-it editors. Free with ads; W3Schools Plus removes ads and adds offline learning. Suited for beginners who want quick examples for nearly any web topic.

Official skill-assessment and practice platform for developers, with challenges in algorithms, languages, AI and databases and recruiter screening. Free practice and contests; recruiter and team plans are paid. Suited for learners and hiring teams alike.

Official cloud IDE and platform that runs code in any language in the browser, with AI assistance and one-click deploy. Free tier with limited compute; paid plans add private projects, more resources and always-on apps. Great for students, hobbyists and quick prototypes.

Official tool that shows you the size, gzip size, dependencies and tree-shake impact of any npm package before you add it to your project, with a clean search and badge widgets. 100% free, supported by sponsorships. Best for JS/TS developers who care about bundle weight.

Official lightweight, no-bullshit, open-source software development platform with mailing-list driven code review, CI via builds.sr.ht, mailing lists, paste, pages and git hosting. Free for public projects; paid plan covers private repos and removes the ad-free nag. Ideal for OSS maintainers and FOSS purists who dislike GitHub's bloat.

Official Glitch free collaborative web app builder and hosting platform with a friendly editor, instant deploys and a remix-friendly community. Free; paid Pro. Best for quickly shipping small web apps.

Official Gitpod cloud developer environments that spin up ready-to-code workspaces from any Git repo, with prebuilds, team plans and a desktop app. Free OSS; paid plans. Best for spinning up dev envs in the cloud.

Official DistroTest free online Linux distribution tester that lets you boot hundreds of Linux distros in a remote VM straight from your browser. 100% free. Best for trying a Linux distro before installing.

Official Tabnine AI code completion tool with on-prem and VPC deployment for privacy, multi-model support and team-aware suggestions. Free; paid Pro/Enterprise. Best for privacy-conscious teams.

Official Stack Overflow AI developer knowledge API that semantically searches 50M+ public questions to ground LLM answers and code generation. Paid OverflowAPI. Best for teams building AI dev tools.