• HTML Validator
• CSS Validator
• CSS Lint
• CSE 154's JS Lint a JavaScript syntax checker (Marty's version)
• Original JS Lint a JavaScript syntax checker by Douglas Crockford of Yahoo!
• HTML Tidy fixes the indentation and validates your HTML code

• FireFox web browser
  • FireBug a FireFox extension for web development
• Chrome web browser
• Notepad++ text editor (Windows)
• Sublime text editor (all operating systems)
• Free Microsoft software for UW students

• Handy HTML Cheatsheet
• HTML and CSS 101
• HTML Vocabulary
• CSS Vocabulary
• CSS Floats
• CSS Flexbox Cheatsheet
• Bootstrap Components

• Animated Loading Icons
• JQuery Fundamentals
• Learn NodeJS with Brigadier Fluffykins
• Interactive ReactJS Introductory Tutorial
• Google Chrome Extension Tutorial (JavaScript)

• Science
  
  • NASA Open API's
  • Open Notify Space Station API's
  • Astronomy API
  • uBio Biological Namebank API
  • Enrichr Gene Database API
• Health
  
  • USDA Food Composition Databases
  • Yummly Recipe and Food API
  • Habitica Gamification API
• Linguistics
  
  • Dictionary API
  • WordNik API
  • Word Cloud API
• Fun/Miscellaneous
  
  • Game of Thrones API
  • Pokeapi Pokemon API
  • Trivia Database API
  • Star Wars API
  • Deck of Cards API
  • IGDB Video Game Data API
  • Data.gov Datasets

• Interactive Guide to Blog Typography

Creative Personal Websites and Resumes

• Mario-Style Resume

Media (Music, Video, Podcasts, etc.)

• Dennis Interactive Video (JavaScript)

Data Visualization

• OMG Particles
• A Life in Data: Nicholas Feltons Self-Surveillance

• CodeStepByStep - Various Programming Exercises in Different Programming Languages!
• Solve the Riddle
• A Google A Day
• Interactive Git Branching Tutorial
• Acorn Electron 1983 Computer Emulator Made with JavaScript