a directory of useful single-page sites and apps.
Animation, Bookmarklets, Colors, CSS, Date & Time, Editors, Grids, Icons, Images, Javascript, Lorem Ipsum, Markup, Math, Misc, Patterns, Photoshop, Reference, Regular Expressions, Responsive Design, Search, Sprites, Starter Kits, Typography, Unicode, Web Performance.

online tools for web dude.
animation, canvas, code snippet, color scheme, converter, css3, favicon, framework, grid, htaccess, html & css, html5, image generator, mind maps, minifier, monitoring, online editor, online service, project, system, text, URI, validator.

Free Webmaster Tools , SEO Tools & Internet Tools.
Online Html Editor, Code Packer, HTML Encoder and Decoder(Encryptor), Difference Comparison, Upper/Lowercase Text Converter, Popup Window Creator, HTML Compression Tool, UnCompress HTML, Alexa Rank Checker, Google Pagerank Checker, Domain Age Checker (Domain Availability), Link Popularity Checker, Backlink Checker, Position Finder, Domain Whois Lookup, Keywords Density Checker, Website Analysis and Stats, Screen Resolution Checker, Screen Resolution Checker(V2), IP LookUP, Color Picker, Strong Password Generator, MD5 Hash Encrypter, CMS Detector, HTTP Header Viewer, QR Code Generator.

Photo Editing Made of Win.

PicMonkey is a feature-rich, free online photo editor that works right in your browser; no downloads necessary. Touch-up tools like Teeth Whiten, Blemish Fix, Weight Loss. Effects like Orton, Cross Process, Color Boost, with drag and drop ease. All the photo editing magic of Picnik, with 78% more monkey.

Search and bookmark a tutorial, article, class, component, forum, as2, as3, actionscript, example, 3D, and tools

A CSS transitions gallery that shows what’s possible with even the most basic of transitions: one property, two values.

HelloQR makes creating, sharing and tracking QR codes super simple and friendly as a kitty.

The responsinator is designed to test responsive websites on different device resolutions.

find that tricky breakpoint.
Enter the url to your site - local or online: both work - and use the controls to adjust the width and height of your viewport to find exact breakpoint widths in pixels. Then use that information in your media queries to create a responsive design.