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Best SEO keyword research tools of 2021

Best SEO keyword research tools
(Image credit: Pixabay)

The best SEO keyword research software tools make it easier to identify important keywords for your website and optimize for them.

The best SEO keyword research tools

Keyword research tools, can be especially helpful to businesses, agencies, and website owners as well for when it comes to trying to improve their Search Engine Optimization.

This is especially important if you want to better understand how to develop targeted traffic streams to your website. This means being aware not just of which keywords you think you want to target, but also checking them against which keywords people are actually using. 

There are a number of tools available that can help provide not just keyword search data, but also generalized traffic analytics to give you an idea of potential traffic volumes for ranking well against these. Additionally, some keyword ranking tools rate keywords based on competitiveness, to give you an idea of the difficulty level of targeting them.

On top of all this, the best keyword search tools will also provide suggestions of related keywords to research as they may provide a better fit between your intended audience and your product or services. Some will even make suggestions based on your existing pages to help improve their targeting and ranking.

Overall, keyword search and research tools are a great way to audit your content and traffic, searching by keyword or topic to gain a better analysis of the keywords your website needs to be targeting to achieve its sales aims.

Here therefore are the best SEO keyword research tools currently available.

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(Image credit: KWFinder)

1. KWFinder

Best keyword analysis tool

Reasons to buy
+Target longtail+Difficulty analysis+Competitor analysis+Seasonal tracking+Affordable plans

KWFinder features the ability to target longtail keywords that may be easier to rank well for while still providing targeted traffic. Not only can you apply a keyword analysis for your own website but you can also use it to analyze other websites for what they are also ranking for, so you can better gauge the competition.

Not only does KWFinder provide keywords to search for, it also includes a lot of key metrics for keyword analysis, including search volumes with historical data. This allows for the identification of long-term trends as well as seasonal keywords you can set up a schedule to target at the right time.

You can also search for local keywords by location in order to specifically analyze what people are searching for in your area, in order to be target customers, especially when engaged in the sales funnel.

At present the software supports tracking of over 2.5 million keywords and supports 52,000+ geolocations.

As a general SEO platform KWFinder may not be as strong as some others, but as a keyword research tool it is excellent.


(Image credit: Spyfu)

2. Spyfu

Best keyword research tool

Reasons to buy
+Competitor research+Organic and PPC +Historical data sets

Spyfu specializes in providing a database of keywords based not just on organic rankings but also of keywords used with Google Adwords. The result is the ability to track not just keywords but also keyword variations used by competitors, in both organic and paid search, allowing for a powerful analysis and keyword research platform.

The keyword research tool itself offers to provide deeper insights than Google's own keyword suggestion tool, with the ability to not just track ranked keywords but also keywords used in PPC campaigns. This means you can source both sets of information for your own keyword research. 

Even better is the ability to identify transactional keywords so you can focus on those keywords that convert traffic better, allowing for keyword quality rather than quantity. You can also distinguish between keywords used for both desktop and mobile devices.

While many SEO tools give preference to organic search, SpyFu provides a lot of PPC data to filter through, which makes it an ideal keyword research tool for both organic and PPC keyword research. 

Although there's no free trial available, Spyfu's paid plans all offer unlimited keyword research volumes, with the only difference between paid plans dependent on the numbers of sales leads and domain contacts, top lists, and API rows returned.


(Image credit: Serpstat)

3. Serpstat

Best keyword suggestion tool

Reasons to buy
+Strong keyword tool+Multiple features+Affordable pricing

The Serpstat Keyword Research tool offers a great platform from which to cover a range of different keyword search and research options.

One feature includes the ability to do competitor research using URL analysis in order to identify keyword potentially missing from your campaigns. Additionally, you can use search questions in order to research specific keyword niches in order to identify further keywords and other ideas for driving targeted traffic to your website.

One of the more interesting options is the "tree-view" to see how keywords are distributed on your pages. While most might target specific keywords at a specific page, sometimes a different page might end up with better ranking potnential, such as by going viral. This tool aims to help you identify other useful pages which, if targeted instead, might improve your targeted ranking for those keywords.

Like other tools there's also the option to search for related keywords, but on top of this there are a number of filters you can use to narrow your selections into the most useful keywords to target.

Starter plans for a single user allow full access to Serpstat tools and data. Pricing is otherwise based on the number of users, so other payment plans are for when multiple users are required to access the account.

Overall, Serpstat offers a lot of interesting flexibility when it comes to keyword research, and the ability to use different tools and methodologies can only be empowering for website owners and SEO's alike.

(Image credit:


Keyword on-site testing

Reasons to buy
+Easy to use and understand+Tests and reports+Useful suggestions+Good for website owners
Reasons to avoid
-Needs a Google Search Console account-Not comprehensive enough for SEO agencies

SEOTesting,com isn't so much a keyword research tool for finding out which keywords you don't use, as much as optimizing for the ones you do use. In this regard it uses your Google Search Console data to generate reports, allowing you to look more closely at the keywords you use, their performance, as well as provides genuinely useful suggestions.

However, doesn't really offer much more than this which makes it's usefulness as a standalone potentially limited, especially when there are big SEO platforms out there that also provide keyword research suggestions.

However, it still manages to provide a very useful niche service. The caveat is that it may not be so useful for big business or most SEO agencies who already have a developed toolkit, but could make for a very useful keyword research tool for small business owners and webmasters who would like a hands-on approach to SEO without having to spend too much money.


(Image credit: Answer The Public)

5. Answer The Public

Best topic research tool

Reasons to buy
+Gain unique insights+Search current trends+Historical data+Free tier available

Answer The Public offers an innovative way in which you can discover current keyword trends in order to improve your keyword targeting by providing additional ideas.

Although there are over 3 billion Google searches a day, up to 20% of these are unique and so won't appear on traditional keyword difficulty and analysis platforms. By using Answer the Public you can the chance to see these important searches and keyword suggestions in order to improve the relevance of your own SEO campaign.

This is not least because you can get a better idea not only of what topics people are searching for on Google but also gain some insight into what they are thinking. This makes Answer the Public a valuable tool not just for SEO agencies  but also for those involved with general marketing and PR.

Even better is that there is a free tier available that allows you to explore the service, although the volume of keyword searches will be limited. If you like what you see you can opt for a paid plan, which allows for unlimited searches, users, and historical metrics.


(Image credit: Google)

Best free keyword research tool

Reasons to buy
+Free+Google data+API

While Google does offer its own keywords suggestion tool for Google Ads PPC campaigns, perhaps it's most valuable tool for keyword insights is Google Trends. This is especially as the internet is a constantly changing and developing medium, and identifying clear patterns in search behavior early enough could provide a long-term competitive advantage.

For example, a sudden rise in search traffic for a particular product or service might offer an opportunity to be targeted through a range of marketing channels, not just for SEO. This was the case during the corona virus pandemic when working from home led to an increase in a wide range of search terms relating to remote working software and work from home equipment such as laptops. 

While that is an extreme example, even under normal conditions celebrity endorsements,  new product releases, and changes to consumer behavior (often driven by new technologies) means that being able to identify such trends can be valuable.

Google Trends offers probably the biggest window on this, not just allowing users to search for specific keywords and identify the trends associated with them, but also by openly providing ongoing trends and highlights. This allows marketers to be able to tap into Google's search data directly for key insights.

Best of all, like all of Google's other SEO tools, Google Trends is free to use. However, the caveat here is that unlike paid-for tools, it means that you're unlikely to be able to work with keywords by volume without being able to connect with the Google Trends API, which in itself adds development costs.

Brian Turner

Brian has over 30 years publishing experience as a writer and editor across a range of computing and technology titles, and has been interviewed multiple times for BBC News and BBC Radio. His specialty on Techradar is Software as a Service (SaaS) applications, covering everything from office suites to IT service tools. He is also a science fiction and fantasy author, writing as Brian G Turner.