Necessary Checking Tools

General website and HTML checks

• Silktide Nibbler – http://nibbler.silktide.com
• Feng-GUI – http://www.feng-gui.com
• W3C markup validation – http://validator.w3.org
• Google Webmaster Tools – http://www.google.com/webmasters/tools
• IE NetRender – http://ipinfo.info/netrenderer/index.php
• HTML Tidy – http://infohound.net/tidy
• Feed – http://validator.w3.org/feed
• Unicorn – http://qa-dev.w3.org/unicorn
• HTML Validator – http://www.htmlhelp.com/tools/validator
• Dr. Watson’s site validation check – http://watson.addy.com
• XML well checker and validator – http://www.ltg.ed.ac.uk/~richard/xml-check.html
• Robots checker – http://tool.motoricerca.info/robots-checker.phtml
• URL checker – http://internetsupervision.com/scripts/urlcheck/check.aspx
• Web page reports – http://www.pinkjuice.com/check

CSS checking

•  W3C CSS validation service – http://jigsaw.w3.org/css-validator
• CSS Compressor – http://www.cssdrive.com/index.php/main/csscompressor

Speed test

•  WebPagetest – http://www.webpagetest.org
• Pingdom Tools – http://tools.pingdom.com/fpt
• WebSiteOptimization – http://www.websiteoptimization.com/services/analyze
• Web Page Content Compression Verification – http://www.whatsmyip.org/http_compression
• Global load time performance – http://www.dotcom-monitor.com/WebTools/technical-tools-browser-test.aspx
• Load Impact – http://loadimpact.com
• google page speed – http://developers.google.com/speed/pagespeed/insights/

Accessibility

•  Browsershots – http://browsershots.org
• Colorblind filter – http://colorfilter.wickline.org
• HERA – http://www.sidar.org/hera/index.php
• html2txt – http://cgi.w3.org/cgi-bin/html2txt?url=URL
• The Readability Test Tool – http://www.read-able.com
• Web Accessibility checker – http://achecker.ca/checker/index.php
• Color contrast – http://www.accesskeys.org/tools/color-contrast.html
• Web accessibily evaluation tool-WAVE – http://wave.webaim.org
• FAE & Functional Accessibility Evaluator – http://fae.cita.uiuc.edu
• Accessibility with style – http://www.sidar.org/hera
• Section 508 – http://www.section508.info

Mobile-readiness

•  mobiReady – http://ready.mobi
• Mobile checker – http://validator.w3.org/mobile

Analyze website

•  Google Analytics – http://www.google.com/analytics

Checking a Blog

• Is My Blog Working? – http://ismyblogworking.com

Testing a sites usability

•  Pingdom tools – http://tools.pingdom.com
• Webpage analyzer – http://www.websiteoptimization.com/services/analyze

Cross Browser Testing

•  Browser shots – http://browsershots.org
• IE net renderer – http://ipinfo.info/netrenderer
• Viewlike – http://viewlike.us

Rate and Grade

• Nibbler – http://nibbler.silktide.com
• Alexa – http://www.alexa.com
• URL Appraisal – http://www.urlappraisal.net

Vulnerabilities checker

• Sucuri SiteCheck – http://sitecheck.sucuri.net/scanner
• HackerTarget.com – http://hackertarget.com

Which language or cms or framework

• Which tools – http://builtwith.com

Above tools more details go to the details of  “check web page for errors”  page.