It takes the assistance of technology to analyze data, conduct research, validate code, and conduct other SEO site audit checks at scale.

The good news is that these tools don’t have to put your SEO budget into the red.

There are plenty of perfectly adequate, free SEO tools available to publishers and SEOs on a smaller scale. And many of these free tools give you access to the same functionality and data sources as the paid versions.

That means that once your needs have outgrown the free version, it’s an easy transition to the paid versions in order to continue on your journey of success.

In the meantime, check out this list of free tools you can use in site audits to get you started.

Free Content-Related SEO Tools

1. SEO Ngram Tool

While we don’t know which came first, the chicken or the egg, we do know that good content starts with understanding the keywords people use and why they’re using them.

The following free keyword tools will help put publishers on the path to top rankings.

A useful free SEO tool that was recently updated for 2022 is the SEO Ngram Tool that was developed by Ryan Jones, Vice President, SEO at Razorfish.

His SEO Ngram Tool helps you to better understand the keyword combinations that are most commonly used for searching.

The tool also generates a search term relationship map, grouping the different search terms into a visual map that shows the base keyword terms (primary connections) and the search terms that are related to it.

Below is an animation showing the main keyword in the center.

Around the main keywords are the primary connections which are variations of the main keywords.

Connected to the primary connections are the keyword phrases that are related to the second-level keyword phrases.

So it's:
Main Level > Second Level Primary Connections > Third level keyword phrases

Animation of Search Term Relationship Map

The data can be downloaded to a CSV spreadsheet that shows word combinations that are frequently grouped together.

Screenshot of Primary Connections taken by author, January 2022

2. Answer The Public

This is a highly popular tool, and it seems like everybody knows about it.

Nevertheless, it needs to be listed for those who haven’t yet heard about it because it’s a great tool.

The way Answer the Public works is you enter first your keyword phrase, and it will return a visualization map of popular keyword phrases that are divided by the kinds of questions, like who, what, where, when, and how.

Screenshot of Keyword Data Visualization taken by author, January 2022

A closeup of the ‘how’ section in the keyword data visualization:

Screenshot taken by author, January 2022

Answer the Public also provides the keyword data in a spreadsheet format, conveniently organized by question type.

Screenshot of an Answer the Public Spreadsheet taken by author, January 2022

3. Ahrefs Free Keyword Tools

Ahrefs offers a multitude of free SEO tools that are worth exploring on their own. One of the tools that stands out is its Free Keyword Research Tool.

It also offers multiple keyword tools that provide 100 top keywords with associated keyword volume and what is represented as Amazon, YouTube, Bing, and Google for search.

Ahrefs commented on the sources of the information:

“Our free tools connect to the same database as our main tools.  The sources are as usual: Google Keyword Planner, clickstream, and data partnerships.”

Regardless of where the data comes from, the tool is a useful resource for generating article writing topics.

4. Siteliner

The free Siteliner duplicate content tool is a scanner provided by CopyScape (an anti-plagiarism service).

Siteliner’s top feature is its ability to identify pages within the site that have similar content. This makes it easy to spot opportunities for improving content.

It’s best for articles to feature content that is unique to each article.

Depending on how much content is similar, articles that share content can create a situation where Google may have to choose which page is more relevant and make one canonical.

Eliminating duplicate paragraphs across articles will help web pages differentiate themselves.

The scanner is limited to 250 pages. Nevertheless, it is useful to alert you to a possible problem with thin pages.

5. W3C Validator

The Worldwide Web Consortium publishes an HTML checker that also checks what the heading outline (H1, H2, etc.) looks like on a web page.

This is a really great tool for checking out how Google sees your web page or a competitor’s web page.

Tick the “Show Outline” option in order to see how your heading elements look to a search engine.

The results can be eye opening and reveal issues with your website template.

Select the Show Outline Box to see headings on a web page. Then, tick the box to show outline. The free HTML validator will show you what your heading tags look like to Google.

The validator can sometimes choke on really bad HTML, but there’s a way to get around the coding errors.

Restart the process, but this time, check the More Options section and choose a document type. The heading checker will work, guaranteed.

Free SEO Website Crawler

6. Screaming Frog – Free For 500 URLs Or Less

Industry-leading site auditing software Screaming Frog offers a free version that’s perfect for auditing smaller sites that are under 500 URLs.

It’s a powerful way to crawl a site and learn if there are any problems.

Screaming Frog automatically provides information about your outbound links, internal links, your images, response codes that various pages give, and information about title tags, meta description tags, headings, images, and pretty much everything about a site that a publisher would want to check for site health and mistakes.

Screaming Frog allows you to set the user agent to emulate Googlebot, Bing, Chrome, and anything else you want in order to see how your site responds, providing a true insight into how the search engines and users are encountering your website.

7. Netpeak Spider

Netpeak Spider is another crawling tool that has a generous free version that can crawl up to 100,000 URLs.

The tool provides data on over 80 SEO-related issues and checks on over 100 technical website issues.

It also has other functionalities related to competitor research.

Overall, the free version of the Netpeak Spider makes a useful complement to the free version of Screaming Frog, as they both have different features and present data in different ways.

8. Xenu Link Sleuth

Xenu Link Sleuth is the old-school SEO tool of choice when it comes to a free site crawler.

It’s described as a broken link checker and it does a great job of that. It generates a report for both internal and external broken links.

But, Xenu does so much more than check for broken links.

Xenu can output a report that provides a quick overview of page titles, orphaned pages, redirects, and pages that are not found (404 response codes).

Xenu Link Sleuth free website crawler and broken link checker.

Free Mobile SEO Tools

Mobile SEO is incredibly important. That’s why it’s essential to be able to test what a search engine results page (SERP) looks like in virtually any city in the world.

It’s also useful to be able to check what your web page looks like in the most popular mobile phones. Pages that look great tend to convert better.

9. MobileMoxie

MobileMoxie provides a fully functional Mobile SEO Tools.

The MobileMoxie SERP checker shows you what the rankings looks like in a huge selection of mobile phone screens.

What makes this tool especially helpful is that it can localize to any city in the world.

Thus, you can test what the mobile rankings are for someone located in any city in the world. This is great for local SEO or for client work where you’re not located in the client’s area.

There is also a MobileMoxie Web Page Checker that can show you what your web page looks like in virtually any mobile phone. This will help you optimize your web page so that it converts the best across a wide range of mobile phones.

The tool is fully functional and can be used for free three times.

Below is the MobileMoxie SERP tester showing a side-by-side comparison of what your SERPs looks like in virtually any mobile phone.

You can also scroll through the local SERPs for any city in the world in virtually any language of your choosing.

Free Website Technical Audit Tools

10. DNS Propagation Checker Tool

The DNS Checker tool will check how well your site is resolving around the world.

This tool can help surface issues with the server settings that can affect the ability of Google and other site visitors from reaching a website.

I have successfully used this tool to identify why Google’s crawler could not reach a website, causing massive indexing issues. The cause was a bad server setting.

So, if search engines or users are having difficulty reaching the website, give the DNS Checker tool a try.

11. MX Toolbox Blacklist Check

This online tool will check if your domain or IP address is on one of several popular blacklists. Being on a blacklist can affect email deliverability.

Free Website Security Audit Tools

Many SEOs don’t consider security as part of an SEO audit.

Security only becomes an issue after a site’s been hacked and the rankings dropped.

In my opinion, website security should be a component of an SEO audit.

A secure website is a major part of how well it ranks and encourages sales. That’s why I include a thorough security audit with every site audit I perform.

12. Free WordPress Vulnerability Scanner: WPScans

This free vulnerability scanner offers a quick but comprehensive scan of potential issues.

Create the report, then research whether or not your site has issues that need fixing. WPScans.com is a useful tool for beginning a security audit.

13. Free HTTPS Validator Tool: SSL Labs Security Checker

The SSL Labs Security tool will spot misconfigurations and security holes in your HTTPS certificate implementation.

Adding a server security certificate is touted as being easy, but that’s not always the case. This useful tool will help you diagnose hidden issues.

14. Free Drupal Security Scanner: Hacker Target Drupal Security Scanner

This comprehensive security scanner will highlight common issues with a Drupal-based website.

Free Website Performance Tools

15. GZip Compression Checker

The GZip Compression tool checks if your site is using GZip compression. Using compression allows your server to download your web pages quickly.

16. YSlow Performance Audit

The free YSlow Performance Audit tool is a comprehensive performance audit scanner. It creates a report of 23 performance rules.

17. GTmetrix

GTmetrix Speed and Performance Audit is another tool that will generate various benchmark scores. Use these scores to understand where your site can be improved.

Bonus: Free Google Site Audit Tools

Google offers many SEO-related tools.

Aside from the Google Search Console, which is very important and is worth mentioning, here are other useful tools provided by Google for auditing and inspecting web pages and websites:

Page Speed Insights offers web page speed feedback.

Rich Results and Structured Data Testing Tool has been consolidated with the Rich Results tool. This helps diagnose issues with your structured data and confirms whether the structured data qualifies for rich results.

The structured data validator does not verify if your structured data conforms with Google’s guidelines.

Make sure you are following Google’s Structured Data Guidelines. Making a mistake with structured data could result in a manual penalty.

Google Lighthouse is a tool that’s built into Chrome. It is also available as a Chrome Lighthouse Extension.

Google’s Lighthouse is an incredible suite of web performance analytical tools.

Learn More About Google Lighthouse: A Technical SEO Guide To Lighthouse Performance Metrics

The Lighthouse SEO report focuses on how well the site can be indexed, which is an especially useful feature these days.

Lighthouse can be used to diagnose on-page issues related to the code and to help find out what’s making a site slower plus it offers tips on how to improve those shortcomings.

Lighthouse is a must-learn tool for everyone who wishes to improve their site performance metrics.

Be Prepared For SEO Success

The quality of free SEO audit tools has continued to grow in usefulness and sophistication.

Publishers and SEOs have the ability to automate hundreds of SEO tasks without paying a thing.

Take the time to learn how to use these tools and you’ll be pleasantly surprised how powerful these tools are.

Success in SEO is never guaranteed or a sure thing.

But the opportunities for achieving your goals have never been better than they are now, with the help of these free SEO tools.

More resources:

Featured Image: Alexander Supertramp/Shutterstock
In-post images #7 to #9 created by author, January 2022