GitHub is the world's largest platform for version-controlled code collaboration, hosting over 420 million repositories and serving 100 million+ developers. Originally a git hosting service, it has evolved into a comprehensive platform for the entire software development lifecycle. Core features: git repositories with pull request workflow, issue tracking and project boards, GitHub Actions for CI/CD automation, Codespaces for cloud-based development environments, Copilot for AI-assisted coding, Pages for static site hosting, and Packages for package registry. GitHub is home to most of the world's open-source software - everything from Linux to Kubernetes, React to TensorFlow, Python to Node.js. It has become the de facto resume for developers, with your GitHub profile often mattering more than a traditional CV. Microsoft acquired GitHub for $7.5 billion in 2018, though it continues to operate independently. Free tier includes unlimited public and private repositories. Teams ($4/user/month) adds advanced permissions. Enterprise ($21/user/month) adds SAML, audit logs, and advanced security.

Stack Overflow has been the essential programmer's Q&A resource since 2008. With over 50 million monthly visits and 20+ million registered developers, it's where programming questions get answered by peers. The unique community-driven format rewards well-researched questions and accurate, detailed answers through reputation points and badges. High-quality answers often include multiple approaches, edge cases, and references to official documentation. While AI assistants like ChatGPT have impacted traffic, Stack Overflow remains invaluable for: obscure error messages, language-specific quirks, deep technical discussions, architectural debates, and historical context on why certain solutions work. The community's fact-checking often catches errors that AI confidently presents. Beyond the main site, Stack Overflow for Teams provides private Q&A for companies, and the broader Stack Exchange network covers dozens of technical fields including DevOps, SysAdmin, and Web Apps.

The complete platform for building and using APIs. Design, test, document, and collaborate on APIs. A must-bookmark resource that's been widely adopted by the developer community. The platform combines an intuitive interface with powerful features that streamline daily workflows for professionals and hobbyists alike. Key highlights include active maintenance, regular feature updates based on community feedback, comprehensive documentation, and integration options with many popular tools and services. Whether you're just getting started or you're an experienced practitioner, this resource offers something valuable. Check out the getting started guide at postman.com to explore all the features.

<p>An indispensable tool for web developers that provides up-to-date browser support tables for front-end web technologies. Check compatibility for CSS properties, JavaScript APIs, HTML elements, and more across all major browsers.</p><p>Features include usage statistics, known issues, and links to relevant specifications. Integrate with your build tools to automatically flag compatibility issues in your code.</p> A must-bookmark resource that's been widely adopted by the developer community. The platform combines an intuitive interface with powerful features that streamline daily workflows for professionals and hobbyists alike. Key highlights include active maintenance, regular feature updates based on community feedback, comprehensive documentation, and integration options with many popular tools and services. Whether you're just getting started or you're an experienced practitioner, this resource offers something valuable. Check out the getting started guide at caniuse.com to explore all the features.

<p>The premier technology news aggregator and discussion forum run by Y Combinator. Hacker News features the most interesting stories about technology, startups, programming, and science, curated by a community of developers and entrepreneurs.</p><p>The comment sections often provide more value than the articles themselves, with industry experts sharing insights and experiences.</p> A must-bookmark resource that's been widely adopted by the developer community. The platform combines an intuitive interface with powerful features that streamline daily workflows for professionals and hobbyists alike. Key highlights include active maintenance, regular feature updates based on community feedback, comprehensive documentation, and integration options with many popular tools and services. Whether you're just getting started or you're an experienced practitioner, this resource offers something valuable. Check out the getting started guide at news.ycombinator.com to explore all the features.

Online tool to learn, build, and test Regular Expressions with a helpful visualization and cheatsheet. A must-bookmark resource that's been widely adopted by the developer community. The platform combines an intuitive interface with powerful features that streamline daily workflows for professionals and hobbyists alike. Key highlights include active maintenance, regular feature updates based on community feedback, comprehensive documentation, and integration options with many popular tools and services. Whether you're just getting started or you're an experienced practitioner, this resource offers something valuable. Check out the getting started guide at regexr.com to explore all the features.

Visualize JSON, YAML, CSV into graph views. Makes complex data structures easy to understand. A must-bookmark resource that's been widely adopted by the developer community. The platform combines an intuitive interface with powerful features that streamline daily workflows for professionals and hobbyists alike. Key highlights include active maintenance, regular feature updates based on community feedback, comprehensive documentation, and integration options with many popular tools and services. Whether you're just getting started or you're an experienced practitioner, this resource offers something valuable. Check out the getting started guide at jsoncrack.com to explore all the features.

Online code editor and community for front-end developers. Test HTML, CSS, and JavaScript instantly. A must-bookmark resource that's been widely adopted by the developer community. The platform combines an intuitive interface with powerful features that streamline daily workflows for professionals and hobbyists alike. Key highlights include active maintenance, regular feature updates based on community feedback, comprehensive documentation, and integration options with many popular tools and services. Whether you're just getting started or you're an experienced practitioner, this resource offers something valuable. Check out the getting started guide at codepen.io to explore all the features.

<p>A fast, offline-capable API documentation browser that combines documentation from multiple sources into a clean, searchable interface. Covers over 500 libraries and frameworks including React, Node.js, Python, Ruby, Go, and more.</p><p>Works offline after initial setup, making it perfect for travel or unreliable internet connections. The fuzzy search is incredibly fast and accurate, often finding what you need in just a few keystrokes.</p> A must-bookmark resource that's been widely adopted by the developer community. The platform combines an intuitive interface with powerful features that streamline daily workflows for professionals and hobbyists alike. Key highlights include active maintenance, regular feature updates based on community feedback, comprehensive documentation, and integration options with many popular tools and services. Whether you're just getting started or you're an experienced practitioner, this resource offers something valuable. Check out the getting started guide at devdocs.io to explore all the features.