- WDG HTML Validator - Excellent tool for identifying syntax errors on pages driven by markup languages. Also has an option to recursively check for errors on every page in the website directory.
- W3C Markup Validation Service - Traverses HTML and XHTML markup for syntax errors. Boasts the title of first (and most used) HTML validator on the internet.
- W3C CSS Validation Service - Checks CSS documents for errors in source code. Also gives warnings for code that doesn’t exhibit the best design practices; e.g. “Same colors for color and background-color in two contexts.”
- RUWF? XML Syntax Checker - Checks for malformed data in XML documents.
- W3C Feed Validation Service - Checks the syntax of Atom and RSS feeds for errors.
- W3C Link Checker - Searches for and identifies broken links. Specifically checks that all the links are dereferenceable, no links and anchors are defined twice and warns about invalid http and directory redirects.
- Juicy Studio Link Analyser - Tests the links on a page for Urls that resolve successfully. Works similar to W3C Link Checker.
- ATRC Web Accessibility Checker - Tests webpages for WCAG 2.0 Level2 compatibility. Generates a report with a series of recommendations for bringing headers, links, metadata, tables and text up to speed.
- WAVE 3.0 Web Accessibility Tool - Highly customizable tool that uses a graphical model to display website compatibility issues with WCAG 1.0 and section 508.
- TAW Web Accessibility Test - Tests webpages for conflicts with WCAG 1.0 compatibility and reports issues via a graphical model. Generates recommendations based upon WCAG priority model.
- HiSoftware CynthiaSays portal - Uses a very strict policy to test webpages for section 508 and WCAG 1.0 compliance. Reports results in an extremely detailed (yet difficult to read) table.
- HERA Accessibility testing with Style - Uses a very sophisticated and easy to read approach to point out WCAG 1.0 compatibility issues with a particular webpage.
- Juicy Studio CSS Analyser - Performs a color contrast test to make sure your sites CSS color scheme meets WCAG 1.0 requirements.
- Juiciy Studio Readability Test - Analyzes the language on your website based upon the Flesch Reading Ease and Flesch-Kincaid grade level algorithms. Useful for determining if you’re speaking over the head of your readers.
- Web Page Analyzer from Website Optimization - An excellent tool that analyzes a webpage and gives recommendations for decreasing loading time. Focuses on optimizing the number of objects, images and overall size of the webpage.
- WebSitePulse Test Tools - A series of tools for identifying website load times and hostname information.
- Internet Supervision Url Check - Generates load times of your webpage from various servers around the world. Useful for determining if your extended audience is actually receiving your message.
- Browsershots - Takes screenshots of your website in various browsers and platforms including Firefox and Internet Explorer on Windows, Firefox and Safari on Mac OS X and Iceweasal and Konqueror on Linux. Unfortunately the tool requires you to wait up to three hours in a processing queue before retrieving your screenshots.
- IE NetRenderer - Generates real time screenshots of your website on Internet Explorer versions 5.5, 6.0 and 7.0.
- MobiReady Report – Analyzes your webpage for compatibility issues on a mobile phone. Generates a detailed report on potential viewing problems and offers a glimpse as to what the website would look like on two different types of mobile phone browsers.
Search Engine Optimization (SEO)
- UrlTrends - Graphically displays a website’s visitor traffic information by search engine prevalence. Extracts information from Google, Yahoo, MSN, Alexa, AlltheWeb, AltaVista and more.
- iWEBTOOL Backlink Checker - Excellent tool for figuring out which sites are linking to yours, and what part of the site they’re linking to.
- iWEBTOOL Multi-Rank Checker - Neatly displays your pages’ Alexa and Google PageRank stats.
- Microsoft adCenter Labs: Advertising and Keyword Research Tools - A fantastic set of tools for analyzing and predicting the audience and market of your website.
- Domain Tools Whois lookup - Comprehensive Whois tool that displays all of the standard domain information and calculates the efficiency of a websites markup when seen through the eyes of a search engine spider.
- SEO-Browser - Strips your website of all the “pretty” components to show you how it looks to a search engine. Very useful tool to make sure your design is on the right track.
- SEO Workers SEO Analysis Tool - Extremely useful tool that analyzes an assortment of page features including meta tags, keyword density and load time.
- SEO Chat SEO Tools - A stock pile of SEO tools for measuring Google AdSense earning potential, keyword density, meta tag effectiveness and much more.