Best Firefox SEO Plugin Tools for Marketers in 2026

Ahrefs SEO Toolbar and SEOquake are the best Firefox SEO plugin tools in 2026, each installed by thousands of active Firefox users. Ahrefs updates regularly; SEOquake's build has stayed unchanged since December 2022 but still works. MozBar also works again as MozBar V5, though Mozilla's listing shows just 172 users.

A Firefox SEO plugin tool is a browser extension that overlays search and ranking data, like domain authority or backlink counts, directly onto pages and search results a marketer already has open. Firefox held 6.51% of the worldwide desktop browser market in July 2026, according to StatCounter, which is why every major SEO vendor here still ships a dedicated Firefox build.

TL;DR

• Ahrefs SEO Toolbar and SEOquake are the strongest all-around picks: both are free for core features, and both show thousands of active Firefox users on Mozilla's official add-on store.
• MozBar is not dead on Firefox. Moz rebuilt it as MozBar V5 (version 5.0.16, released July 3, 2026), though the listing shows only 172 users as of August 2026.
• SEOquake's Firefox build has not changed since December 22, 2022, and Mangools' since April 3, 2020; both still install and run.
• Keywords Everywhere installs free, but search-volume and CPC (cost-per-click) data spend paid credits, starting at $84 a year for 100,000 credits on the Bronze plan.
• Mettevo's SEO team pins Ahrefs SEO Toolbar and SEOquake to Firefox for daily audits, and treats the rebuilt MozBar as too new for client work yet.

What Are Firefox SEO Extensions, and Why Do They Still Matter in 2026?

Firefox SEO extensions, sometimes called Firefox SEO addons or Firefox SEO plugins, are small programs installed through Mozilla's Add-ons store that add SEO data panels directly to the browser. A marketer checks domain authority or backlinks without opening a separate dashboard.

These tools split into two groups. Toolbars such as MozBar, Mangools, and Ahrefs SEO Toolbar show authority and backlink metrics for the page that is currently open. Overlays such as SEOquake and Keywords Everywhere inject keyword or SERP (search engine results page) data directly into Google's results.

Firefox SEO Extensions Compared: Price, Metrics, and Whether They're Still Alive

The table below lists each extension's official Firefox build, not its Chrome numbers, since install counts and update dates differ by browser.

Sources: each tool's official Firefox listing on Mozilla's Add-ons store, linked in the sections below, accessed August 2026.

Is SEOquake Available for Firefox?

Yes, SEOquake is available for Firefox, published as SeoQuake SEO extension by the SeoQuake Team. The Firefox build shows 12,910 active users and a 4.5-star rating across 157 reviews, according to Mozilla's Add-ons store. SEOquake itself is not a Semrush product, even though it pulls Semrush backlink data as one of several sources. Semrush's own knowledge base describes SEOquake as a free plugin compatible with Firefox, Chrome, and Opera.

SEOquake's free features include an SEO Audit report and a keyword density breakdown, plus internal and external link analysis. It also compares index counts across Google, Bing, Yahoo, and Baidu, and none of that requires an account. Mozilla's store also lists an unrelated add-on called SEOquake Extension from a different developer, so confirm a listing shows SeoQuake Team as publisher before trusting its data.

Does MozBar Still Work on Firefox in 2026?

Yes, MozBar works on Firefox again in 2026. Moz rebuilt the extension as MozBar V5, and Mozilla's official listing shows version 5.0.16, released July 3, 2026, requiring Firefox 140 or later. The listing describes the update as completely re-engineered.

Despite the rebuild, adoption has not caught up. The Firefox listing shows just 172 users and a 5-star rating from only 2 reviews, too small a sample to treat as validated. That gap between an actively updated build and a near-empty user count is easy to misread as MozBar being abandoned on Firefox, when the add-on store itself shows otherwise. Checking Mozilla's own listing directly, rather than trusting an older summary, is the only way to get a current answer.

MozBar's own listing describes three access tiers. The Guest tier, which needs no account, gives free access to on-page elements and general attributes, plus internal link details. A free Moz Community account adds Domain Authority (DA) and Page Authority (PA) scores on top of that. A paid Moz Pro subscription unlocks Spam Score and page optimization data, plus domain analysis and keyword ranking queries.

Ahrefs SEO Toolbar on Firefox: What's Free and What Needs a Subscription

Ahrefs SEO Toolbar ships a Firefox build with the same feature set as its Chrome version, and installing it costs nothing. Mozilla's listing shows the extension published directly by Ahrefs, at version 3.2.10, released July 23, 2026, with 4,736 active users and a 3.3-star rating from 27 reviews.

The free tier covers seven features, according to Ahrefs' own help documentation:

• On-page SEO report.
• Redirect tracer with HTTP headers.
• Outgoing-links report with a link highlighter and broken-link checker.
• SERP positions.
• Local search results simulator.
• Web Vitals.
• Keyword ideas and People Also Ask (PAA) results.

A paid Ahrefs subscription adds the vendor's own metrics for visited pages and sites, plus keyword volume and difficulty in search results and Google Trends. The toolbar's Web Vitals panel reports Core Web Vitals, the same three metrics Google itself uses for page-experience signals, per Google's own documentation. Google recommends a Largest Contentful Paint (LCP) within 2.5 seconds, an Interaction to Next Paint (INP) under 200 milliseconds, and a Cumulative Layout Shift (CLS) under 0.1. One limit: the metrics bar spends one row from your monthly Ahrefs export allowance per URL, though disabling it avoids that cost.

Mangools SEO Extension for Firefox: Free Metrics on a Six-Year-Old Build

Mangools' Firefox extension is free to install, but Mozilla's listing shows it unchanged since April 3, 2020, the oldest last-update date here. Version 2.2.16 has 706 users and a 3.5-star rating from 24 reviews. It still installs and runs on current Firefox, but Mangools has not shipped a Firefox-specific update in six years.

The extension pulls two sets of metrics, per Mangools' own product page.

• Authority data: Domain Authority (DA) and Page Authority (PA) from Moz, Citation Flow (CF) and Trust Flow (TF) from Majestic, plus referring domains and a popularity trend.
• On-page data: a Google SERP snippet preview and word counter, a Google index and headings hierarchy check, plus a Page Speed checker.

Without a Mangools account, the extension shows only the popularity trend. A free account unlocks DA, PA, CF, and TF. For keyword research, Mangools links to KWFinder, whose free plan allows 5 lookups every 24 hours with 15 related and 5 competitor keywords, according to Mangools' KWFinder page. That cap resets daily, so it suits a marketer checking a few terms, not a full content calendar.

Keywords Everywhere on Firefox: How the Credit Pricing Works

Keywords Everywhere installs free on Firefox, but every search-volume, CPC, or competition lookup spends a paid credit. Mozilla's listing shows the extension published by Axeman Tech, at version 11.53, released July 15, 2026, with 6,885 users and a 4.4-star rating from 407 reviews. One credit buys volume data for exactly one keyword, regardless of how many results appear on the page, according to Keywords Everywhere's own credit-usage documentation.

The entry Bronze plan costs $84 a year for 100,000 credits and one user seat, which works out to roughly 1,190 keyword lookups per dollar, according to Keywords Everywhere's pricing page. Three higher tiers scale from there:

• Silver: $168/year, 400,000 credits, 3 seats.
• Gold: $480/year, 2,000,000 credits, 10 seats.
• Platinum: $1,440/year, 8,000,000 credits, 20 seats, plus priority support.

Which Firefox SEO Extensions Should You Avoid in 2026?

None of the five extensions here are truly dead on Firefox, but two carry a real staleness risk. SEOquake's official build has not changed since December 22, 2022, and Mangools' extension has not changed since April 3, 2020. Both still install and run, but neither developer has fixed anything Firefox-specific in years, so a future compatibility break is a real possibility.

MozBar is the opposite case. It looks abandoned from the outside, since its Firefox user count sits at just 172. Moz's own listing tells a different story: an actively rebuilt V5, current as of July 2026. Treat any claim that "MozBar doesn't work on Firefox" as unverified unless it links to Mozilla's listing to prove it.

Are SEO Browser Extensions Free?

Most Firefox SEO extensions are free to install, but their metrics often depend on a separate account or paid subscription. SEOquake and Ahrefs SEO Toolbar's core features work without any account at all. MozBar and Mangools show only basic data until you add a free vendor account, and Keywords Everywhere spends a paid credit on every search-volume or CPC lookup, starting at $84 a year.

Inside Mettevo's Firefox SEO Stack: What We Actually Run Daily

Mettevo's SEO team keeps two Firefox extensions pinned to the toolbar for every client audit. Ahrefs SEO Toolbar handles on-page checks, redirect tracing, and Web Vitals. SEOquake gives a fast read on keyword density and index counts across search engines during technical reviews. Neither needs a paid account for a first-pass audit, which keeps the initial review free regardless of the client's tool budget.

MozBar is not part of that default setup yet. The rebuilt V5 version is too new and too thinly reviewed, just 2 reviews on its own listing, to trust on client work without more testing. Mangools stays out of the Firefox rotation entirely, since its Firefox build has gone six years without a vendor update. The team uses Mangools' browser-independent web app instead when a project calls for Citation Flow or Trust Flow data.

Keywords Everywhere gets installed on demand for content briefs that need a quick volume check, with credits bought per project rather than kept on a standing team subscription. For deeper keyword planning, the team still opens Google Keyword Planner's free tier alongside whichever Firefox extension is already open.

How to Choose the Best Firefox SEO Extension for Your Workflow

Check what an extension can see before installing it. Firefox extensions that read every page you visit need host permissions. Mozilla's own developer documentation confirms that host permissions let an extension read page content and tab data for every matching site; reading cookies needs a separate "cookies" permission too. The browser prompts for confirmation at install time. Mozilla's guidance is direct: avoid unnecessary permissions, and explain why each is needed. An SEO toolbar needs broad host access to read metrics off every URL you open, but a request for payment details or camera access is a reason to skip the install.

Match the extension to the task instead of picking one tool for everything:

• Full-site technical audits: Ahrefs SEO Toolbar's on-page report and Web Vitals panel.
• Fast SERP and index checks: SEOquake.
• Keyword volume while drafting content: Keywords Everywhere, budgeting credits per project.
• Authority context while browsing: MozBar's Guest tier or Mangools, weighed against their live user numbers.

None of these five extensions replace a full SEO platform. For deeper competitor and backlink research beyond what a toolbar shows one page at a time, see our comparison of free Ahrefs alternatives. For ongoing client work, Mettevo's SEO services combine these free extensions with paid platform access.

FAQ

Which SEO extension is best for Firefox?

Ahrefs SEO Toolbar and SEOquake are the strongest picks for Firefox in 2026. Both are free, both are published by their vendor or a long-running team, and both show thousands of active Firefox users on Mozilla's add-on store. Ahrefs SEO Toolbar covers on-page audits and Core Web Vitals; SEOquake covers keyword density and multi-engine index data.

Is SEOquake available for Firefox?

Yes. SEOquake's official Firefox listing, published as SeoQuake SEO extension, shows 12,910 active users and a 4.5-star rating from 157 reviews on Mozilla's add-on store. It is free to use and provides an SEO Audit, keyword density report, and link analysis without an account. It is not itself a Semrush product, though it displays Semrush backlink data as one of several metrics.

Are SEO browser extensions free?

Most are free to install, but the metrics behind them often are not. SEOquake and Ahrefs SEO Toolbar's core features work without any account. MozBar and Mangools show only basic data until you create a free account with that vendor. Keywords Everywhere installs free but spends paid credits on every search-volume lookup, starting at $84 a year for 100,000 credits.

Does MozBar still work on Firefox?

Yes. Moz rebuilt MozBar as MozBar V5 for Firefox, and Mozilla's add-on store lists version 5.0.16, released July 3, 2026, requiring Firefox 140 or later. The rebuild is real and current, not a leftover listing. Adoption still lags, though, with just 172 users shown on the Firefox add-on page as of August 2026.

What is the best free SEO tool for Firefox?

For a fully free workflow, pair SEOquake with Ahrefs SEO Toolbar: neither requires a paid account for its core features. SEOquake covers on-page audits, keyword density, and index comparisons across four search engines; Ahrefs SEO Toolbar adds redirect tracing, broken-link checks, and Core Web Vitals. Together they replace most of what a paid toolbar bundle offers, at no cost.