Inspired by a forum post I came across the other day I’ve compiled a list of free online checkers/validators for web developers. Please let me know if you’re aware of others. (Updated 16th September 2010)
(X)HTML
- validator.w3.org/ – The daddy of validators and your first port of call
- validator.nu/ – Maybe your second port of call. Slightly more experimental validator
- www.htmlhelp.com/tools/validator/ – WDG markup validator with batch capability
- gsnedders.html5.org/outliner/ – HTML5 outliner (sections, headings, etc.)
XML/FEEDS
- validator.w3.org/feed/ – W3C RSS/Atom Feed validator
- www.w3.org/RDF/Validator/ – W3C RDF/XML Validator
- schneegans.de/sv/ – XML schema validator also good for XHTML
CSS
- jigsaw.w3.org/css-validator/ – W3C CSS validator
- htmlhelp.com/tools/csscheck/ – WDG CSS validator
MOBILE
- validator.w3.org/mobile/ – W3C mobile checker
- ready.mobi – Provides a score on mobile suitability
- iphonetester.com/ – An iPhone/iPod Touch emulator
ACCESSIBILITY
- www.accessify.com/tools-and-wizards/accessibility-tools/favelets/quick-page-test/ – Bookmarklet highlighting a page’s inaccessible elements
- www.cynthiasays.com – Use for guidance on Section 508 and WCAG compliance
- wave.webaim.org – Web accessibility evaluation tool
- www.checkmycolours.com/ – Check foreground and background colours for sufficient contrast
- achecker.ca/checker/ – Web accessibility checker (URL or file upload)
- soap.stanford.edu/accessibilitychecker – Another web accessibility checker (URL or file upload)
- webaim.org/resources/contrastchecker/ – Handy colour contrast checker
- fae.cita.illinois.edu/ – Functional accessibility evaluator
- juicystudio.com/services/image.php – Image analyser to check for accessibility issues
- graybit.com/main.php – Test a page’s perceived contrast by converting to greyscale
LINKS
- validator.w3.org/checklink/ – W3C link checker
- www.htmlhelp.com/tools/valet/ – WDG link checker
MICROFORMATS
- microformatique.com/optimus/ – Microformats transformer
- hcard.geekhood.net/ – hCard microformat validator
OTHER
- browsershots.org – Check a page’s appearance in multiple browsers
- ipinfo.info/netrenderer/ – Check a page’s appearance quickly in IE
- www.prchecker.info/check_page_rank.php – Check your Google page rank
- web-sniffer.net – HTTP request & response header viewer
- www.yellowpipe.com/yis/tools/lynx/lynx_viewer.php – View sites as text only
- www.jslint.com – Eye-opening JavaScript syntax checker
- www.w3.org/2008/03/basificator.html – Convert (X)HTML to XHTML Basic 1.0 or 1.1 for mobile use
- www.webpagetest.org – Check your page load performance
- resizemybrowser.com – Resize your browser window or tab to reflect the size of various devices
- software.hixie.ch/utilities/cgi/data/data – Data URI creator
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