SEO Tools

Firefox plugins:

Chrome:

Tools:

Check microdata:-

https://www.google.com/webmasters/tools/richsnippets and Webmaster Tools

http://www.seo-browser.com/ how googlebot sees your site

HTTP Headers – http://livehttpheaders.mozdev.org/ , http://www.rexswain.com/httpview.html , etc

See what Google bot sees – http://lynx.browser.org/

Cheat sheets:

Urls – https://seomoz.app.box.com/shared/g4ju1fc4it

SEO for Web Dev – http://moz.com/blog/the-web-developers-seo-cheat-sheet-2013-edition

Colinbancmedia cheat sheet – http://www.cheatography.com/colinbancmedia/cheat-sheets/onsite-seo-cheatsheet/

A guide to search operators http://www.seomoz.org/blog/25-killer-combos-for-googles-site-operator

Sources/ Further Reading:

http://www.dzone.com/articles/10-seo-tools-every-web

http://www.smashingmagazine.com/2006/09/22/complete-list-of-best-seo-tools/

http://www.alvit.de/handbook/

http://www.htmlgoodies.com/beyond/seo/

Build your own SEO tools

http://www.programmableweb.com/news/45-seo-apis-google-adsense-alexa-and-yahoo-site-explorer/2012/10/09
http://www.programmableweb.com/category/seo/mashups?category=20275
https://moz.com/ugc/api-blog-post-10970
http://www.programmableweb.com/apis
https://moz.com/blog/futuristic-ways-of-creating-automated-link-building-tools
http://mrcoles.com/blog/technical-look-seomoz-automated-link-building-tool/
https://mentionmonitor.googlecode.com/svn-history/r4/trunk/monitor.py
https://code.google.com/p/mentionmonitor/source/browse/trunk/monitor.py
http://www.mattbeswick.co.uk/big-list-of-apis/
http://www.thegenielab.com/blogs/thegenielab-blog/14856811-7-seo-apis-to-supercharge-your-campaign
http://www.annexcore.com/blog/ultimate-list-apis-enhance-seo/
http://www.brightonseo.com/using-apis-build-seo-tools-workshop/
http://www.pattonwebz.com/seo-impact/build-your-own-seo-tools-for-free-part-1/
https://builtvisible.com/building-simple-seo-tools/
https://moz.com/blog/api-and-dataset-cheatsheet-building-quick-dirty-tools
https://www.distilled.net/blog/seo/how-to-build-agile-seo-tools-using-google-docs/
https://builtvisible.com/playing-around-with-importxml-in-google-spreadsheets/