Nearly every SEO browser extension installs free. The difference is what works once it's installed: on-page checkers and developer toolbars usually give you everything straight away, while extensions that show keyword or domain data often need an account, an API key or a purchased plan for the richer numbers. Choose by the data you need.
Every extension on this list installs free, so the useful question is what happens after you click install. Some give you their whole toolbox at once. Others show a slimmed-down view until you sign in, add a key or buy a plan, and that's where most of the disappointment comes from.
So I've sorted eight free SEO extensions by what the free install gives you, as each vendor's own page describes it, as of Nov 2026. They're in no particular order, and nothing is crowned. Where a page states no limit, I've kept the line short rather than guess.
What a free install covers, and what needs an account
On-page checks are the generous part. Headings, meta tags, schema, broken links and page speed are things an extension can read straight from the page you're on, so most tools here give them away with no account at all.
Data is the part that sits behind a login. Search volume, keyword lists for a whole domain, rank tracking and inbound link data come from the vendor's own databases, and that's where you'll meet a sign-in, an API key or a plan. One extension on this list makes this explicit: its prompt templates and link data work without a key, but search volume needs an API key and a purchased plan. Another shows domain trends without an account, and full metrics with one.
My advice on building a free SEO toolbar
Start with one on-page checker and one keyword-volume extension, and stop there until you notice a gap. That pair covers most everyday jobs: checking a page before it goes live, and seeing roughly how often people search for a phrase while you're in the results.
Add a developer toolbar if you work on site builds, and an account-based extension only when you know which locked feature you'll use. Installing eight at once slows your browser and buries the one reading you wanted under seven you didn't.
Free SEO extensions side by side
| Tool | What it shows | Good for |
|---|---|---|
| Detailed SEO Extension | Page-level insights | One-click views of on-page elements and schema |
| Keyword Surfer | Keyword volumes | Search volume and keyword ideas inside Google results |
| Keywords Everywhere | Data overlay | Extra SEO and social data on pages you visit |
| Mangools SEO Extension | Metrics toolbar | Domain trends plus unlimited on-page and speed checks |
| SEO Minion | On-page checker | Twelve on-page checks from one sidebar |
| SEOquake | Audit toolbar | Page audits, URL comparisons and exports |
| Sitechecker SEO Chrome Extension | On-page overview | Content and link overviews on any page |
| Web Developer | Dev toolkit | Inspecting how a site is built |
Eight free SEO Chrome extensions, in no particular order
Detailed SEO Extension
Best for: One-click page checks of on-page elements, indexing signals and schema, with shortcuts into other tools; free forever with no upsells, the vendor says, on Chrome and Firefox.
Keyword Surfer
Best for: Seeing search volume and keyword ideas with an overlap score right inside Google results; the vendor calls it free forever, and it's offered for Chrome only.
Keywords Everywhere
Best for: Layering SEO, YouTube and social data onto pages you visit; prompt templates and inbound link data work free, but search volume needs an API key and a purchased plan.
Mangools SEO Extension
Best for: Quick domain metrics, SERP tools and unlimited on-page and speed checks, per the vendor; without an account you get trends only, domain-level data and no rank tracking.
SEO Minion
Best for: Running twelve on-page checks from a sidebar, including headings, broken links, SERP preview and hreflang; no account or API key needed, the vendor says, on Chrome, Firefox and Edge.
SEOquake
Best for: Auditing a page from your toolbar, checking internal links, comparing URLs and exporting the data to a file; a free download, per its page, separate from its browser checker.
Sitechecker SEO Chrome Extension
Best for: Getting an on-page overview, content analysis and link overview on any page; core features are free, the vendor says, while GSC Insights, Issues and Monitoring need an account.
Web Developer
Best for: Developers checking how a site is built by inspecting or disabling page parts; distributed free with optional donations, per its maker, for Chrome, Edge, Firefox and Opera.
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Two kinds of free install
Free with nothing behind it. SEO Minion, Detailed SEO Extension, Web Developer and SEOquake give you their listed features without an account, as their pages describe them. Keyword Surfer belongs here too: its page calls it free forever and states no cap, so there's nothing more to add.
Free toolbar, richer data behind an account. Keywords Everywhere works free for part of its data and needs a key and a plan for search volume. Mangools SEO Extension gives trends and on-page checks without an account, with full metrics once you link one. Sitechecker SEO Chrome Extension keeps its core features free and asks you to log in for Search Console insights and monitoring.
If you'd rather check pages without installing anything, these free SEO checkers that run in the browser do the job from a web page, and our longer guide to SEO extensions for Chrome goes beyond the free installs.
Keeping your browser lean
Each extension you add can read the pages you visit, so check the permissions it asks for before you install. Turn off the ones you only use now and then, and switch them on when you need them. You'll keep your browser quick, and you'll know which toolbar a number on the page came from.
Do you make a free SEO browser extension? Tool makers can ask to be considered for a featured place on this list.
Want your tool on this list? Featured spots and reviews here are paid partnerships. Here's how to partner with me.
Frequently asked questions
Are free SEO Chrome extensions safe?
Most well-known ones are, but every extension can read the pages you visit. Check the permissions before you install, keep the number small and remove any you stop using.
Which free SEO extension shows search volume?
Some show search volume free inside Google results, while others need an API key and a purchased plan before volume appears. Read the extension's own page to see which kind you've got.
Do I need an account to use SEO extensions?
Not for on-page checks. Many extensions give headings, meta tags and schema with no account. Domain metrics, rank tracking and keyword lists more often need you to sign in.
Do SEO extensions slow down my browser?
They can, especially when several run on every page. Keep only the ones you use often switched on, and turn the rest on when you need them.
Can a browser extension replace a full SEO tool?
For quick checks on single pages, often yes. For site-wide audits, rank tracking over time or large keyword research, you'll usually need a dedicated tool behind an account.
Do these extensions work in browsers other than Chrome?
Several do. Some list Firefox, Edge or Opera versions, while others are offered for Chrome only. Each vendor's own page lists the browsers it supports.
