Written by Crystal Ortiz. Updated on 25, June 2025
We tested the most recommended SEO extensions. This list shows you the 22 best free ones.
Learn how to use these tools to boost your SEO without spending money.
The SEOTesting Chrome extension helps with daily tasks and on-page SEO.
Top features:
This gives you Google Search Console data while browsing. You don’t need to open the SEOTesting dashboard every time. That saves big time.
Free features available to everyone:
The document structure feature helps confirm content and headings are correct.
Pro tip: Click on any heading to scroll to that element. Hover your mouse to highlight it.
Grammarly offers a free browser extension. It gives grammar, spelling, and tone suggestions. This keeps your writing sharp everywhere.
This extension helps you avoid awkward mistakes.
Grammarly’s free plan is generous. You can set a preferred tone. This helps you write consistently.
Why it matters for SEO: Good writing improves user experience. Better content often ranks higher.
These tailored suggestions make Grammarly easy to use.
Keyword Surfer shows search volume and CPC for keywords in the SERP.
They have search volume data for over 70 countries. This includes the USA, UK, Australia, France, and Germany.
SERP features:
The title rewrite feature is a game-changer. Google often changes title tags now.
The sidebar widget shows:
Press the star to save keyword ideas to your clipboard.
Racoon SEO Link Checker is a free extension. It helps you track and manage links in one browser window.
Find every link on a page. Check the health of each one. See if it’s indexed and has correct attributes.
Key features:
This saves time on manual link checking. It makes link management more efficient.
Glimpse enriches your Google Trends experience.
Features include:
Glimpse helps spot new trends before they go mainstream. This helps you become an authority on new topics. SEO competition stays low early on.
Subscribe to their newsletter. Get 2 exponential trends per month in your inbox.
Free plan: 10 searches per month. Just create an account to start.
SimilarWeb shows key website metrics instantly.
Metrics displayed:
The extension is 100% free. You just need to join their contributor network. This means you share information about sites you visit with SimilarWeb.
Great for competitor research. Pair it with SimilarSites for deeper insights.
Similar Sites shows related websites to the one you’re viewing.
Main use case: Finding your main competitors. This helps when you don’t know much about a niche. You don’t have to rely on guesswork.
This extension helps SEO agencies research competitor sites for new clients.
Click the extension icon when visiting any site. It shows a panel with data.
The panel also shows estimated monthly visitors for competitors. See their ranking in the category too.
You need to sign up for the SimilarWeb contributor program.
Schema.dev created this extension. It helps you see a page’s markup.
The extension helps you write Schema. It also validates existing Schema on pages. Fix any errors with little effort.
Easy to use and test markup with one button click.
Schema Builder works great for adding structured data to ecommerce stores.
The extension shows markup requirements and recommendations when you test and deploy.
This extension shows how browsers render pages versus original source code.
SEOs use this to see what the DOM looks like. This shows what search engines see.
Catch errors before Google does. Otherwise, Google might index the improperly rendered version.
This prevents errors caused by JavaScript during rendering. Examples include missing titles and meta descriptions.
Three code sections:
Link Redirect Trace (LRT) helps diagnose and analyze redirect errors.
This extension differs from alternatives. It shows errors, how to fix them, and their impact on your site.
Features:
Everything is free. No account creation needed.
SEO Search Simulator simulates Google searches from different locations in real time.
You don’t need VPNs to see how pages rank in different countries. It removes personalized Google results too.
Great alternative to logging into rank tracker tools for quick checks.
Also helpful for checking competitor rankings for specific queries.
The search simulator saves searches. Handy when you use the same query repeatedly.
The Detailed SEO Extension helps with on-page SEO checks.
Overview section shows:
Detailed has shortcuts for robots.txt and XML sitemaps. But they guess where these files are located. If files don’t exist, shortcuts lead to 404 pages.
Other features:
SEO Minion has many capabilities. The SERP preview function shows how title and meta description changes look in search results.
This prevents you from following SEO tool character recommendations that cut off titles and descriptions.
Everyday tasks:
On-page elements it finds:
SERP widget shows:
Bonus feature: Download People Also Ask (PAA) questions and answers as CSV files for research.
MozBar analyzes pages for free. It checks load time, canonicals, status codes, and markup.
In SERPs, this extension shows Moz’s popular metrics: Domain Authority (DA) and Page Authority (PA).
Free plan includes link metrics from 3 places:
Common use case: Link-building campaigns. See which top SERP results have the highest authority.
Link Grabber collects all links from HTML pages with one button click. It displays them in a list.
A great tool when Screaming Frog is unavailable. Perfect for quick checks. Copy links into spreadsheets for analysis.
Features:
Hunter’s browser extension finds email addresses on the web easily.
The free plan includes 25 searches per month. Enough for occasional use.
When Hunter finds email addresses on sites you visit, it lights up (turns orange). Stays gray when it doesn’t find any. The extension works in the background.
Click the extension icon. See a pop-up with known email addresses and URL sources where they were found.
The Siteimprove Accessibility Checker finds insights about website accessibility.
This tool lists all accessibility issues. Shows how often they happen on pages. It points to elements responsible for warnings.
The accessibility checker helps when advising potential clients. Show examples of how they can improve accessibility compliance.
Straightforward extension for improving web experiences for users with disabilities.
SEOQuake handles a wide range of SEO tasks for free.
Quick page diagnosis shows:
Google SERP features:
Also includes an ‘SEO bar’ for browsing with domain metrics.
NoFollow highlights nofollow links on web pages with visual indicators.
This extension makes link analysis much faster. Instead of checking HTML code, you see nofollow links instantly.
Key features:
Why it’s useful:
Perfect for link builders who need to assess link value quickly. Also helps with internal link audits.
Redirect Path shows the complete redirect chain for any URL you visit.
When pages redirect multiple times, this extension maps the entire journey. You see every step and status code.
Features include:
Common use cases:
Essential for technical SEO audits. Helps prevent PageRank loss from poor redirects.
META SEO Inspector displays meta tags, headings, and images in an organized format.
This extension gives you a quick on-page SEO overview without viewing source code.
What it shows:
Visual indicators:
Perfect for:
Saves time compared to manual source code inspection. Great for content creators and SEO beginners.
Tag Assistant helps you install and troubleshoot Google tags on your website.
This official Google extension works with gtag.js and Google Tag Manager. It shows which Google tags are present on any page you visit.
Core features:
Troubleshoot mode:
Perfect for:
Essential for any site using Google’s marketing and analytics tools. Helps ensure your SEO efforts get properly measured and tracked.
After years of testing, these five extensions form the core of my daily SEO workflow:
Start with these five. Add others based on your specific needs.
These 22 free extensions have transformed how I approach SEO work. They’ve helped me:
The best part? Every tool costs nothing. You can build a professional SEO toolkit without spending a penny.
Remember: Extensions are just tools. They work best when you understand SEO fundamentals. Use them to enhance your knowledge, not replace it.
I regularly update this list as new extensions emerge and existing ones evolve. The SEO landscape changes fast. Your toolkit should adapt with it.
Ready to take your SEO analysis to the next level?
While these free extensions provide excellent value, sometimes you need deeper insights.
SEOTesting goes further than any extension ever could:
Get started with SEOTesting’s free features today! We have a 14-day free trial for you to make use of, so you can decide whether the tool is worth it for you and your team. Once you’ve finished the trial, we start at just $50 per month!
Note: While SEOTesting is a paid tool, our Chrome extension provides valuable free functionality that every SEO professional can benefit from.