Thanks to Kevin Gibbons, Irish WonderNick Chowdrey and Pete Handley for their suggestions. 

Keyword research and content planning

Google’s Keyword Planner. Used as described in this article, the keyword planner can be a valuable tool for identifying opportunities and finding ideas for content. 

faq fox. This is a useful tool for finding popular questions that people ask in your industry. 

Yandex Keyword statistics. For those targeting the Russian market. 

Baidu Keyword Tool. As above, for China. 

Google auto complete. 

Google Auto Complete

Ubersuggest. Enter a phrase and ubersuggest will provide a bunch of suggestions around that term. 

On site tools

Searchmetrics. The research section is free and gives us so much juicy info.

Screaming Frog SEO Spider. This is useful for identifying a multitude of on page factors and highlighting where there are issues (with page titles and descriptions being too long or too short, finding broken links or internal redirects that need to be updated).

Schema Creator. If you want to look at how to start getting rich snippets in Google Search results, but don’t know how to write the code for it? Schema Creator can help you generate this depending on the type of rich snippet and structured data you need to implement.

Page Speed checkers

Google Page Speed Insights. Speed matters, and this tool will score sites for speed, with some useful suggestions for improvement. 

WebPageTest. Along with Pingdom, these tools provide insights into the elements that may slow page loading. 

Pingdom

Link analysis

Majestic. Another good top-level analysis of backlink profiles that comes free.

Broken links checker. Does what it says on the tin… 

ahrefs. The free version provides good top-level backlink analysis. 

SpiralDB. This is handy for doing a quick check on a web page for a domain, using LinkRisk, Majestic, ahrefs and SEMrush data. 

Other tools 

Jellyfish Google penalty checker. This looks at site data, plotting Google updates on a timeline. 

Copyscape. This looks for sites copying your pages. 

Wayback Machine. Here’s what we looked like in 2001…

theMediaFlow’s HREFLANG XML sitemap generator. This can be used to generate international targeted XML sitemaps for various languages and regions.

Moz. The pro tools here contain lots of useful data, including link analysis, social analytics and keyword tracking. 

PI Datametrics. This paid tool allows you to track your own and competitors’ rankings over time, and shows which pages are ranking at any given time. Its especially useful for avoiding issues with cannibalisation of ranking by competing pages from the same site.

Jellyfish search snippet tool. This allows you to test how your page will look in the SERPs. 

Google Webmaster tools (which as of the date of this article being published has been rebranded Search Console). Essential for checking crawl errors, keywords, and any notifications from Google. 

Spyfu. This provides competitive intelligence, both organic and PPC visibility data, as well as historic rankings with Google update clues over the timeline and a handy option to compare two or more sites and the chance to spy on competitors’ profitable keywords. 

 

BuiltWith Technology Profiler. A really useful tool to understand what web technologies are employed on a website – server types, content management systems, code frameworks and much more.

Buzzsumo. Among other things, this can analyse the performance of content and the backlinks each article attracts. 

 

SearchStatus. A Firefox plugin offering quick access to data about a site including Whois, Google indexing of the site, link report for a page, etc.

SEMRush. This provides organic visibility and PPC visibility data, as well as some useful data on competitors: 

Archive.orgCheck what a site looked like in the past, how long has a site existed on a domain etc.

Ayima Pulse. This provides insights into rankings and movement in various sectors. 

Which tools do you use? 

This is a long list, but we may have missed some useful SEO tools. Please suggest any below and let us know why they’re useful to you. 

(Bear in mind, our spam filter tends to frown upon links in comments, so just provide the name of the tool rather than the URL.)