There are some great applications and tools available for designers and developers on the web. Some are more useful than others but here is a list of some I regard quite highly at the moment.
JSFiddle is a great tool for testing and sharing your code snippets. The advantage that JSFiddle has over other code sharing apps is that you can test code which utilises popular JavaScript frameworks such as jQuery, MooTools, Prototype and Dojo to name just a few.
ChopApp has been developed by the great people at Zurb and again is a code snippet sharing application. Each snippet has it's own unique URL. You can also comment on certain lines of code and save it for the author to see. Great for debugging and error testing.
As CSS3 becomes the standard for many emerging websites, you still can't ignore the millions of users still using legacy browsers. To combat this, "generator" apps are good for cross-browser compatibility and great time savers. The Ultimate CSS Gradient Generator also has FireFox and Chrome extensions available so you don't have to visit the site each time to create your gradients.
Similarly, the 3D Ribbon Generator helps you create pure CSS ribbons. The markup is slightly weighty with this generator but still useful nonetheless.
Placehold.it is quite an understated but useful tool for web designers. Although most designers tend not to design their sites in the browser, Placehold.it makes it easy if you do. It's sort of like a lorem ipsum for images.
Dabblet is the work of Front-End Web Developer, Lea Verou. A tool for testing your CSS with one difference. You can save all your snippets as gists on GitHub. A really useful app.
For the lazy ones, the AJAX Loader generator allows you to download cool animated progress bars and spinners for your site.
Patternizer pretty much does what it says - creates patterns BUT for the HTML5 <canvas>
tag. Rather than CSS, Patternizer gives you JavaScript markup to add to the <canvas>
.
I often find myself downloading a font which is TrueType only. TTF2EOT converts your TrueType font to an Embedded OpenType for free.
As a Web Designer or Developer, you juggle jobs during your day. StrikeApp is another brainchild from Zurb which is a to-do list that can be shared (with unique URLs) with managers and colleagues. You can also choose from 5 different themes.