Like most web developers or SEO professionals, I use a vast array of tools to get the job done. I use a combination of desktop and web applications, some purchased and some free. Everyone I know has downloaded a free copy of Mozilla Firefox, but few realize that by installing some of the 1,500 free extensions they can eliminate the need for most of the other applications they currently use. Below are my 13 favorite extensions for web professionals (in no particular order):
HTML Validator (http://users.skynet.be/mgueury/mozilla/) validates web pages to the W3C HTML standards with a simple green check in the corner of the page if the page validates, a red check if it doesnt, and a yellow exclamation point if there are warnings. It also includes an enhanced view of source code that allows you to see where errors are within the code.
FireFTP (https://addons.mozilla.org/firefox/684/) free, secure, cross-platform FTP client that provides easy and intuitive access to FTP servers. This eliminates a piece of software for those of you who use a separate program for FTP.
Professor X (https://addons.mozilla.org/firefox/2823/) lets you view header information without...