As an Internet marketing strategy, SEO considers how search engines work, what people search for, the actual search terms or keywords typed into search engines and which search engines are preferred by their targeted audience. Optimizing a website may involve editing its content, HTML and associated coding to both increase its relevance to specific keywords and to remove barriers to the indexing activities of search engines. Promoting a site to increase the number of backlinks, or inbound links, is another SEO tactic.
The tool to replace Google’s popular keyword tool has been derided by some, but still offers data not available anywhere else.
The most popular of all the analytics tools available, Google Analytics continually innovates and sets the standard.
Google Analytics API
The Google Analytics API is great for building custom reports and tools, and also for pulling data straight into Excel or Google Docs.
Google Map Maker
Among other things, Google Map Maker allows you to contribute to public map information, which may be shared and incorporated into Google Maps.
Google PageSpeed Insights
Tools, data, and insights to improve your page speed. Page speed is correlated with beer rankings and user engagement, so this maers.
Google Public Data
Drawing on vast public databases, Google public data offers a great starting point for content research, infographics, and more.
Google SERP Snippet Optimization Tool
Technical SEO, CRO
That SEO Mofo! Use this tool to see how your snippet may appear in Google’s search results. Add structured data, review stars, and more.
Google Structured Data Testing Tool
Structured Data, Technical SEO
If you use Schema.org microformats or any other type of structured data, this tool will verify your markup.
See what’s trending in Google search results and view keyword search popularity over time. A must for trends.
Tools Suite, Diagnostic
The interface recently received an overhaul, and Google Webmaster remains a must‑have resource of diagnostic and health tools for site owners.
Bing Webmaster Tools
Tools Suite, Diagnostic
Similar in function to Google Webmaster Tools, Bing offers a suite of interesting research tools and resources for webmasters.
Domain Hunter Plus
This magic extension for Chrome not only helps you find important broken links, but also tells you if the links point to an available domain.
Free tools for creating and sharing inforgraphics. The templates allow anyone to create a professional‑looking graphic.
Email Format helps you find the proper structure for thousands of companies and organizations across the web.
The ultimate Google+ directory that’s great for research, outreach, and link building. Sort by keywords, profession, country, and more.
Frobee Robots.txt Checker
Robots.txt, Technical SEO
Many robots.txt files contain hidden errors not easily visible to humans. Run your file through this tool and you never know what you’ll discover.
This awesome local SEO tool scores your local SEO visibility and gives you actionable next steps to raise your score.
Pingdom offers an entire suite of speed tools to help analyze page load, DNS issues, and connectivity.
Piwik is a lightweight web analytics solution, and a great alternative to Google Analytics.
Toolbar, Tools Suite, Technical SEO
More raw data than any other SEO toolbar out there.
Want to see the history of your website or your competitor’s site? The Wayback Machine allows you to step back in time and track important changes.
Quick and easy website speed tool. Offers suggestions for improving performance.
Wordstream Free Keyword Tools
Keyword Research, Tools Suite
In addition to its paid offerings, Wordstream offers a suite of free keyword tools offering access to thousands of keyword suggestions.
XML‑Sitemaps offers probably the easiest sitemap creation solution anywhere. Great for smaller sites when you need a sitemap in minutes.
Link Research, Link Building
One of the more popular link research tools, Ahrefs offers a large index and nice anchor text distribution charts. Mostly a paid tool, but they offer some free data.
Top Free SEO Tools List