The short version: for free on-page checks, start with Detailed SEO Extension or SEO META in 1 CLICK. For link work, add NoFollow, Redirect Path and Robots Exclusion Checker, which are fully free. SEOquake and the Ahrefs SEO Toolbar give the most free features in one install. MozBar shows DA and PA only with a free Moz account.
Below are 13 Chrome extensions, each checked on its own Chrome Web Store listing on 30 October 2026: what the free version includes, the user count, the star rating and when it was last updated. Every row links to the listing we read. Extensions change often, so if something has moved, tell us and we'll update it.
How we checked
- The official listing only. We read each extension's Chrome Web Store page, and for Wappalyzer its pricing page too, and recorded the free features as the developer describes them. User counts and ratings are the rounded figures the store displays.
- What we did not do. We didn't run accuracy tests on the authority or traffic numbers some of these show. Those numbers are each vendor's own estimates, and they disagree with each other by design.
- What we dropped. SEO Minion was on our shortlist, but its listing now says it "is available only to customers" of a paid Keywords Everywhere plan, so it's no longer a free tool. We also left out general developer extensions (Web Developer, Lighthouse) that aren't built for SEO work.
Comparison table
| Extension | What it does | Free version (checked 30 Oct 2026) | Users / rating | Best for |
|---|---|---|---|---|
| Detailed SEO Extension | Title, meta, robots, headings and links of any page | Fully free | 600,000 / 4.8 (233) | A fast on-page snapshot |
| SEO META in 1 CLICK | Meta tags, headings, images, links, robots.txt and sitemap | Fully free | 1,000,000 / 4.9 (1.3K) | Checking meta data in one click |
| SEOquake | Page audit, SERP overlay, link analysis, keyword density | Core reports free without an account; a free Semrush account adds Authority Score and referring domains | 1,000,000 / 3.5 (2.6K) | The most free features in one extension |
| Ahrefs SEO Toolbar | On-page data, link highlighting, redirect tracing, broken links | Core tools free; Ahrefs metrics need a paid subscription | 400,000 / 4.7 (563) | Link highlighting and CSV export |
| MozBar | DA, PA, link highlighting, on-page elements | Guest mode free; DA and PA need a free Moz account; Spam Score needs Moz Pro | 900,000 / 1.3 (2.5K) | Seeing DA and PA as you browse |
| Keywords Everywhere | Traffic estimates, Moz link metrics, related keywords | Free version includes traffic estimates and Moz link metrics; search volume is paid | 1,000,000 / 3.3 (5.7K) | Moz link metrics in the free version |
| Similarweb | Traffic estimates, sources, top keywords, AI referral traffic | Free, but you must approve anonymised browsing data collection first | 1,000,000 / 4.6 (3.8K) | A rough traffic check on a partner site |
| Check My Links | Finds broken links on the page you're on | Fully free | 100,000 / 4.6 (107) | Broken link building prospecting |
| NoFollow | Outlines nofollow, ugc and sponsored links; flags noindex | Fully free | 100,000 / 4.3 (234) | Checking a placed link's attributes |
| Redirect Path | Shows 301, 302, 404, 500 and JavaScript redirects, plus headers | Fully free | 300,000 / 4.3 (200) | Spotting redirects behind a link |
| Link Redirect Trace | Redirect chains, canonicals, robots rules at every step | Free to install | 100,000 / 4.8 (367) | Deep redirect and canonical checks |
| Robots Exclusion Checker | robots.txt, meta robots, X-Robots-Tag, canonical, AI bot blocks | Fully free | 50,000 / 4.9 (29) | Confirming a page can be indexed |
| Wappalyzer | Detects the CMS, frameworks and tools a site runs on | Extension free; a free account adds 50 technology lookups a month on the website | 3,000,000 / 4.0 (2K) | Knowing the CMS before you pitch |
Four of these are free with no account and no upsell at all: Check My Links, NoFollow, Redirect Path and Robots Exclusion Checker. If you install nothing else, those cover most of the link checks a site owner does by hand.
On-page checks
Detailed SEO Extension
One click shows the title, meta description, meta robots, canonical, headings and link counts for the page you're on. It's quick, clean and fully free, and at 4.8 stars from 233 ratings it's one of the best-reviewed tools here. Worth knowing: the store now lists AHREFS PTE. LTD. as its developer. It was last updated on 2 June 2026. If you want one on-page extension, this is a safe pick.
SEO META in 1 CLICK
It shows the same core on-page data plus Open Graph tags, image alt counts, and links to the site's robots.txt and sitemap. With 1,000,000 users and 4.9 stars from 1.3K ratings, users clearly like it. The catch is age: the last update was 31 August 2024. It still does the job, but the two on-page tools overlap, so pick one.
SEOquake
SEOquake, from Semrush, packs the most into a free install: a page audit, a SERP overlay with position numbers, internal and external link analysis with follow status and HTTP codes, and keyword density. Its listing says core reports work without an account, and a free Semrush account adds Authority Score and referring domains. Its rating is a middling 3.5 from 2.6K ratings, and the overlay can feel busy, so turn off the parts you don't use.
Ahrefs SEO Toolbar
The free core includes on-page data, link highlighting, redirect tracing, broken link spotting and CSV export of the links on a page. Ahrefs metrics such as referring domains and traffic only appear with a paid subscription, and the listing says so plainly. At 4.7 stars from 563 ratings, it's the strongest all-round link inspector here when you don't need the metrics.
Authority and traffic
MozBar
MozBar has three tiers on its listing: guest mode is free for on-page elements and internal link details, a free Moz account adds Domain Authority and Page Authority, and Spam Score needs Moz Pro. Its rating is the lowest on this list, 1.3 stars from 2.5K ratings, so read the recent reviews before you rely on it. If DA is the number your link partners talk in, it's still the quickest way to see it; for other ways, see how to check Domain Rating and DA for free.
Keywords Everywhere
Most people know it for search volume, which is paid. The free version is more useful to link builders than you'd expect: its listing includes website traffic estimates and Moz link metrics (DA, Spam Score, referring domains) at no cost. Rated 3.3 from 5.7K ratings. Good for sizing up a list of sites worth contacting.
Similarweb
Similarweb shows estimated visits, traffic sources, top countries and top keywords for the site you're on, and now an estimate of traffic from AI chatbots. It's free, but the listing says you must approve the collection of anonymised clickstream data on the domains you browse before it works. That's the price. Treat its numbers as rough estimates, useful for telling a real site from an empty one, not for precise comparisons.
Link checks
Check My Links
It scans every link on the current page and marks the broken ones, and the latest version also checks links in Google Docs and Sheets. That makes it the classic tool for broken link building: open a resource page, run it, and you know in seconds whether there's a dead link to offer a replacement for. Fully free, updated on 21 October 2026. For checking your own whole site rather than one page, use a crawler instead (how to find broken links on your site).
NoFollow
NoFollow outlines nofollow, ugc and sponsored links and flags noindex meta tags, so you can see at a glance whether a link passes signals. It's the simplest way to confirm the attribute on a link someone placed for you. Fully free, updated on 1 September 2026. If the difference is new to you, start with dofollow vs nofollow links.
Redirect Path
From Ayima, it flags 301, 302, 404 and 500 responses plus meta and JavaScript redirects as you browse, and shows the HTTP headers and server IP. The listing says the processing happens on your computer. A link that points to a URL which redirects twice is weaker than it looks; this shows you that without opening developer tools. Fully free.
Link Redirect Trace
From LinkResearchTools, it goes deeper than Redirect Path: every step of a redirect chain, with the canonical, robots.txt and noindex status at each hop. Rated 4.8 from 367 ratings, but it hasn't been updated since 15 June 2024. Use it when Redirect Path shows something odd and you need the full picture.
Robots Exclusion Checker
It shows whether robots.txt, the meta robots tag, the X-Robots-Tag header or the canonical is stopping the page you're on from being indexed, and highlights nofollow, ugc and sponsored links. It also flags whether the site blocks AI crawlers (14 bots across 6 companies, per the listing). A link on a page Google can't index does little, so this is the check people most often skip. Fully free, 4.9 stars.
Site profiling
Wappalyzer
Wappalyzer tells you what a site is built with: CMS, ecommerce platform, analytics and more. For link building that answers a practical question before you pitch, such as whether the site runs WordPress and can easily edit an old post. The extension is free, and its pricing page says a free account adds 50 technology lookups a month on the Wappalyzer website. At 3,000,000 users, it's the most installed tool here.
A two-minute partner check with free extensions
Before you agree a link with another site, you can confirm the basics with the free tools above:
- Is the page indexable? Open the page that will carry your link and check Robots Exclusion Checker. Red means a noindex or a robots.txt block.
- Do the existing links pass signals? Turn on NoFollow. If every outbound link on the page is nofollow, yours probably will be too.
- Does the URL redirect? Redirect Path shows whether the page is the final URL or a hop in a chain.
- Is anyone visiting? Similarweb or Keywords Everywhere gives a rough traffic estimate. Near zero is a warning sign.
- What authority does it have? MozBar (free account) or SEOquake (free Semrush account) gives a third-party score. Use it to compare, not as a verdict.
The full version, with what to do when a check fails, is in how to vet a link swap partner.
A word on permissions
Extensions that read every page you visit need broad permissions. The Chrome Web Store shows each developer's data disclosure under "Privacy" on the listing. Most tools here state they don't collect or use your data; Similarweb is the clear exception, and says so before you start. Install only what you'll use, and remove the rest.
Where Backlinkster fits (ours)
Backlinkster is our product, so weigh this accordingly. It isn't an extension. It's a link exchange where site owners trade 1-for-1 in-content links, and each swap is verified by API, which covers two of the checks above for you: whether the link is live and whether it's a normal dofollow link. If manual checks are the part of link building you'd rather not do, see how it works. The free plan includes 5 swaps a month.
FAQ
What is the best free SEO Chrome extension?
For a single install, SEOquake gives the most free features (page audit, SERP overlay and link analysis) and works without an account. For quick on-page checks, Detailed SEO Extension is simpler and better rated. Most people end up with two or three small tools rather than one big one.
Is MozBar still free?
Partly. Its listing describes a free guest mode for on-page elements and link details, Domain Authority and Page Authority with a free Moz account, and Spam Score only with Moz Pro. As of 30 October 2026 it holds a 1.3-star rating from 2.5K ratings.
Which Chrome extension shows if a link is nofollow?
NoFollow and Robots Exclusion Checker both highlight nofollow, ugc and sponsored links, and both are free. MozBar, SEOquake and the Ahrefs SEO Toolbar also show follow status as part of their link reports.
Can a Chrome extension check backlinks?
Not in full. Extensions show the links on the page you're looking at, plus link counts from the vendor's index if you have an account. To see every site linking to yours, use Google Search Console or a backlink tool; see what is the best backlink tool.
Can I cite or reuse this comparison?
Yes. Please link to this page as the source and note the date we checked the listings (30 October 2026), since free versions change.
How to cite this page: Backlinkster, "Free SEO Chrome Extensions Compared (2026)", checked 30 October 2026, https://backlinkster.com/resources/free-seo-chrome-extensions
Related: How to vet a link swap partner · Dofollow vs nofollow links · What is the best backlink tool? · How to check Domain Rating and DA for free · Free email finder tools compared · What is a redirect chain?