CSS frameworks

See my CSS frameworks section.

JavaScript frameworks

See my JavaScript frameworks section.

Sites

World Wide Web Consortium (W3C)

Can I use …
Compatibility tables for support of HTML5, CSS3, SVG and more in desktop and mobile browsers.
Web technology for developers | MDN
Web technology documentation at Mozilla developer network
HTML Dog
HTML, CSS and JavaScript tutorials
Flat UI Colors
This small web app helps you to copy the colors from [Flat UI].
MDN - Mozilla Developer Network
Shared knowledge for the Open Web, in particular see Learning the Web.

REST API Tutorial

Code Guide by @mdo
Standards for developing flexible, durable, and sustainable HTML and CSS.
structure exposed
View a website’s skeleton by resetting all styling to browser default.
HTTP STATUS DOGS
Hypertext Transfer Protocol Response status codes. And dogs.
HTTP Status Cats API
Usage: https://http.cat/[status_code]. If you need for some reason to use an image extension, add .jpg to the URL.

CDN

JSDLIVER

RawGit

MAXCDN

See also CDNperf
finds you fast and reliable JavaScript CDNs that make your websites snappy and happy!
unpkg
unpkg is a fast, global content delivery network for stuff that is published to npm.

Site templates

Initializr
Start an HTML5 project in 15 seconds!
HTML5 ★ BOILERPLATE
The web’s most popular front-end template
TEMPLATED
A collection of many free CSS and HTML5 site templates, designed & built by Cherry + AJ and released under the Creative Commons.

Do not miss Motherfucking Website and …

  1. Better Motherfucking Website
  2. Best Motherfucking Website
  3. The Best Motherfucking Website

Validators

W3C Markup Validation Service
Check the markup (HTML, XHTML, …) of Web documents
W3C CSS Validation Service
Check Cascading Style Sheets (CSS) and (X)HTML documents with style sheets
Validator.nu
HTML5 Validator (by WHATWG)
PageSpeed Insights
Make your web pages fast on all devices (by Google).
The AMP Validator
Interactive validator for Accelerated Mobile Pages (by Google).

HTTP

HTTP/1.1: Status Code Definitions

HTTP/2 FAQ

Browser testing

BrowserSync
Time-saving synchronised browser testing.
LiveReload
The Web Developer Wonderland

Fonts

Google Noto Fonts
Beautiful and free fonts for all languages
Type Terms
If you are new to typography or here to refresh your memory, then Type Terms is the perfect tool for you.
Hack
A typeface designed for source code
Font Awesome
THe iconic font and CSS toolkit
Fontello
Icon fonts generator
Font River
20,000 downloadable fonts and dingbats for Windows and Mac
Fira Sans
Firefox OS Typeface
Google Fonts API
helps you add fonts to any web page, see also all available fonts
Google Noto Fonts
Beautiful and free fonts for all languages
Ubuntu Font Family
A unique, custom designed font that has a very distinctive look and feel
Adobe Font - Source Code Pro
Monospaced font family for user interface and coding environments

Icons

Icon finder

X-Icon editor

Evil Icons

Feed Icons

Code Icons
An icon set of programming languages, frameworks, and coding tools.
Flat icons
Free icons for both personal & commercial use.
Icons8
38700 free icons, the largest icons pack ever.

Favicon & App Icon Generator

Online editors

See Online JavaScript IDE on Wikipedia for a comparison table.

Codepen
Front End Developer Playground & Code Editor in the Browser
Leaveweave
HTML5, CSS3 & JavaScript playground for web designers & developers
bl.ocks.org
viewew for D3 code examples histed on GitHub Gist
cssdeck
HTML5, CSS3, JS Demos, Creations and Experiments
Plunker
an online community for creating, collaborating on and sharing your web development ideas
JS Bin
Collaborative JavaScript Debugging
Cloud9 IDE
an online IDE for client and server development
Bootply
The Bootstrap Playground
JSFiddle
Test your JavaScript, CSS, HTML or CoffeeScript online
Koding
an online IDE which allows software developers to program and collaborate online in the browser
Nitrous.io
Create a {Node.js, Ruby, Python, Go} Development Environment in 60 seconds
Codio
THE WORLD’S MOST POWERFUL WEB IDE
CodeSandbox
CodeSandbox makes it easier to create, share and reuse React projects with others

Articles

Client side

Web Design in 4 minutes
a nice interactive tutorial

Don’t Forget to Cover Your Client Side!

Working With Intl
ECMAScript Internationalization API

Remote Desktop Client with AngularJS and Yeoman

7 Principles of Rich Web Applications

Presenting The Most Over-Engineered Blog Ever

Introducing Pokedex.org: a progressive webapp for Pokémon fans

Server side

The CK10 problem

Scaling to Millions of Simultaneous Connections

To close or not to close

How we built analytics.usa.gov

Hosting

Amazon Web services

Linode

Firebase
Build Realtime Apps

SoftLayer

DigitalOcean

OPENSHIFT
The Open Hybrid Cloud Application Platform by Red Hat

Joyent

heroku

DreamHost

Cloud At Cost

demos

WebGL

GPU fluid experiment

tanx
WebGL game on PLAYCANVAS