Web Development Resources

Online development resources and tools.

Cheat Sheets

jQuery and Javascript
Terminal and Command Line
CSS and SASS

PHP Libraries for your projects

Free Front-End Online Validation and Analysis Tools

Pingdom Website Speed Test
Page performance and load tests.

Web Page Test
Page performance and load tests.

W3C HTML Validator
Check the markup validity of Web documents in HTML, XHTML, SMIL, MathML, etc.

W3C CSS Validator
Check Cascading Style Sheets (CSS) and (X)HTML documents with style sheets.

jSon Validator
Validate jSon objects.

HTML5 Document Outliner
Checks the heading outline structure of your HTML5 document.

HTML5 Semantic Analyzer
This tool tries to extract some information from a HTML semantic-rich document. It only uses information available through a good usage of the semantics defined in HTML.

Atom, RSS and KML Feed Validator
This is a validator for syndicated feeds. It works with RSS 0.90, 0.91, 0.92, 0.93, 0.94, 1.0, 1.1, and 2.0. It also validates Atom feeds.

REDbot HTTP Resource Analyzer
Checks HTTP resources to see how they’ll behave, pointing out common problems and suggesting improvements. Although it is not a HTTP conformance tester, it can find a number of HTTP-related issues.

Google Webmaster Tools
Get data, tools and diagnostics for a healthy, Google-friendly site.

Free Online Coding Tools

CodePen
A frontend playground for HTML, CSS and JS.

Pixels to EM Converter
Even if you use SASS mixins to convert your sizes, it’s always useful to have a reference chart.

Character Entity Converter
Entity Conversion Calculator for CSS hex, Javascript hex, and decimals.

CSS Clip-Path Maker
Clippy online CSS clip-path maker.

Free Fonts, Pics, Design Assets and Content

Freepik

Local Tools

Viewport Resizer
Viewport Resizer is a bookmarklet which wraps your viewport with a UI to test responsive designs quickly. It’s not a device emulator, but as far as quick UI behavior goes, it’s pretty sweet and totally customizable.

Interesting Services

Inspirational and Educational Resources

DavidWalsh.name
Personal blog of Mozilla Sr. web developer and MooTools core developer David Walsh.