Serpstat Chrome Extension Guide 2026: Website SEO Checker, Tab by Tab

What the Website SEO Checker does

Serpstat's browser extension, the Website SEO Checker, shows SEO data for any page you visit: on-page checks, ranking keywords, domain traffic and backlinks ^[1]. You open a site, click the icon and get a panel of Serpstat's core analysis data without opening Serpstat itself. It is a quick check, not a full report. That is the point. The panel has three main tabs, SEO Parameters, Page Analysis and Domain Analysis, plus a settings menu for language, credits, history and on-page highlighting. Since version 3.6.0 it reopens on the last tab you used, which is a small touch that saves clicks.

It runs in Google Chrome, Firefox, Microsoft Edge and Opera, and it installs from each browser's official store; search for Serpstat Website SEO Checker. Safari is not on the list. Our short verdict: it is a handy, light way to look at any page's SEO data and to spot keyword gaps on competitors' articles. It draws on Serpstat's API, and the newest help article ties that to the Team plan. Install it during a Team trial, and keep it if you keep Team.

Free to install, paid to run

The extension itself costs nothing to install. Using it is another matter, because every analysis calls Serpstat's API, and the help article says API credits are consumed with each analysis request. Serpstat's own pages then disagree about who can use it. The extension page says it is "available for all pricing plans, including the free users after signing up, with a limited number of credits" ^[2]. The help article dated May 5, 2026 says you need API credits and "API access is available from the Team plan" ^[1]. We treat the newer help article as current.

If the help article is right, the practical cost of the extension is the Team plan itself, $129 a month or $100 a month on annual billing ^[3], because a token without API credits returns nothing. A free install that needs a paid plan to work is not really free. On the other hand, a team already paying for Team gets the extension at no extra subscription cost beyond the API credits it spends. We could not confirm whether Freemium tokens still work today, so test it on your own account. Our Serpstat pricing guide covers what Team includes.

Installing it and adding your token

Setup is short. Install the extension from your browser's store, open your Serpstat account, generate and copy your API token, then paste it into the extension's token field. Browse to any site and click the icon. The help article sends you to Profile, then API token, while the extension page says to copy it from the My Profile section. There is one token per user account, and team members use their own tokens and credit allocations. If a Freemium token returns no data, the plan question above is the reason. Try a Team trial token instead.

The token links the extension to your account and your credit pool, so treat it like a password. Since version 3.5.1 it is hidden in the settings menu and shown only when you click a button, which protects it during screen shares. Still, never record a demo with it visible. If you suspect a leak, generate a new token in your profile, and the old one stops working.

SEO Parameters: the page-health view

SEO Parameters covers domain authority, meta tag quality, image count and size, external link volume, microdata quality, site loading speed and technical errors. Open it first on any page you plan to fix or copy. The authority score is Serpstat's Domain Rank, rated 0 to 100 from the sites linking to a domain and the sites linking to those. It is Serpstat's own metric, so compare it only with other Serpstat DR scores, never with another vendor's authority number.

Tags, links and headings

The panel checks title and description quality, and color tags flag robots meta conditions such as noarchive, noindex and nofollow. A red noindex on a page you want ranked is the fastest win the extension will ever give you. The settings can highlight headings, alt attributes, external links and nofollow or noindex links on the live page, and since version 3.6.0 a highlight stays on across pages until you switch it off. Turn on one at a time. The page gets busy fast. Version 3.6.0 also added a visual tree of the h1 to h6 hierarchy, so a missing h1 or a jumbled order shows immediately. On product pages, alt-text highlighting shows gaps at a glance.

Schema, speed and server checks

The panel reports microdata quality, and version 3.3.5 added Schema.org to the site structure section. It shows what markup a page carries, but for a full validation use Google's own tools as well. Site loading speed is a rough signal only. One load from your browser says more about your connection than about real users, so use field data from your analytics for decisions. Version 3.5.0 added a Tools section that checks server response codes and shows response headers, so a chain of 301s shows each hop. That is handy during migrations.

The extension also shows Open Graph markup and alternate and hreflang tags, which makes a quick hreflang check per page easy on multilingual sites. It shows the IP address of the analyzed site, IPv4 and IPv6, and the services and technologies the site is built with. Those are prospecting details. They tell you what platform a competitor uses. For a whole site, though, run Site Audit, because the extension sees one page at a time.

Page Analysis: the reason to install it

Page Analysis is the tab with the most value. It shows the keywords the current page ranks for, the competing pages in search results for those keywords, and the keywords competitors rank for that this page is missing. The first block lists the queries the open page ranks for, from Serpstat's database. For a competitor's best article, that list is a ready outline of what the article covers in Google's eyes. The competing pages block gives you the field for the topic. Open two or three of them and you have the landscape without running a single full report.

The missing-keywords block is the best reason to install the extension. It shows queries competitors rank for on this page that your own site does not cover, and the help article pitches it as a 30-second keyword gap check on any competitor page. From Page Analysis you can also switch to expanded reports in the Serpstat interface. The panel shows a preview and the app shows the whole report, and each expanded report spends credits in the app's own pools. Use the panel to decide what is worth opening.

Domain Analysis: a snapshot of any site

Domain Analysis shows traffic, visibility and keyword count for the domain, with new, lost, rising and falling keywords, a one-year visibility graph and a backlink summary. It is enough for a first call with a prospect. Traffic comes from Serpstat's estimate, which has used a machine-learning model since August 2025, and visibility follows Serpstat's own scale. Both are estimates. Use them to compare sites with each other, not to quote a client's real visitor count. A sudden spike in lost keywords is worth a look, and the full Site Analysis report in the app shows which ones and when.

Version 3.6.1 added backlink analysis to this tab. The panel shows domain rank, referring domains and links, and top pages, which is a quick read before outreach; for a full link profile, open Backlink Analysis. Indexing is another place where the pages disagree. The help article says Domain Analysis shows indexing across Google, Bing, Baidu and Alexa, while the extension page names Google and Bing. Treat indexing counts as rough either way. Finally, choose the search region in settings before you start. Keyword data comes from that country's database, depth varies by country, and a US database on a German site shows the wrong picture.

Credits, request limits and empty panels

The settings show how many credits are left, and Team includes 200,000 API credits a month. Neither Serpstat page gives a credit price per panel view, so we cannot tell you exactly what one check costs. The extension page gives free and paid plans the same rate: 1 request per 5 seconds and up to 100 requests per day. At that pace, a full day's 100 requests take at least eight minutes of clicking, by our arithmetic. Most users never reach the cap. It matters mainly to people who treat the extension as a bulk tool.

When data does not load, the help article lists three checks: the token is entered correctly, the account has API credits, and Serpstat has data for the site. Data availability depends on whether Serpstat has indexed that domain or page, so new or low-traffic domains may show little or nothing. An empty panel on a new site is normal. It does not mean the extension is broken. On Freemium, the plan question explains most failures. On Team, check credits first, then the token. If you only open the panel now and then, turn off the autostart switch for SEO Parameters in the settings menu.

Five jobs it does well

The extension answers quick questions about one page or one domain. It does not plan a site. The app runs audits, rank tracking, clustering and batch analysis, and the panel is best used to choose what to research next there. Within that role, a handful of routines stand out. Each takes minutes. These are the ones where it pays off:

• The 30-second gap check. Open a top-ranking competitor article, click the icon, go to Page Analysis and note the missing keywords with high volume and low competition. Add them to your own article or plan a new one, then repeat on the next two results.
• Auditing a competitor page. Read SEO Parameters, then the headings tree and the structured data block, then Page Analysis. Five minutes, no full report, and you know what you must beat.
• Vetting link partners. Open each candidate site and read Domain Analysis and Domain Rank. Drop sites with no traffic or a collapsing visibility graph before you write a single email.
• Checking your own launch. Right after publishing, check meta tags, headings, robots tags and response codes. A stray noindex or a redirect chain shows at once.
• Client calls. Walk a prospect through Domain Analysis and the one-year graph, which clients understand quickly. Hide the token first, and save the full audit for the proposal.

How it has changed, and why old pages disagree

The extension launched for Chrome in April 2018. A February 2020 rebuild, updated in July 2020, added Firefox, Opera and Edge and a long list of features, and users of the first version received the update automatically. Most of today's panel comes from that rebuild. The 2020 post logs versions from 3.3.0 in October 2019 to 3.6.1 in April 2020, and we found no newer version log on the pages we read. The current help article, from May 5, 2026, describes the features without version numbers. It is a mature tool.

Its limits have shifted along the way. The April 2018 launch post gave free accounts 100 requests a day and paid plans 1,000, and the 2020 rebuild post kept the same split ^[4]. The current extension page says 100 for both. Trust the newest page. Older posts keep older limits, nobody updates them, and the newest product or help page is the only safe guide to what the extension allows today.

Next to MozBar, Ahrefs and Semrush

Moz offers MozBar, which it says shows its top SEO metrics for free as you browse. Serpstat's extension shows its own metrics, and its Page Analysis tab adds missing keywords for the page. If you need Domain Authority by name, use MozBar; for keyword gaps, use Serpstat. Ahrefs lists an SEO Browser Extension among its free tools. We did not compare the two side by side, but Ahrefs' strength is backlinks while Serpstat's panel adds keyword gaps, and many SEOs run both. The Semrush pages we read list free web checkers, such as a website traffic checker and a keyword tool, rather than a browser extension.

Who should install it, and who will outgrow it

Install it if you are a Serpstat Team user who researches competitors' content, a link builder vetting sites, or anyone launching pages who wants a quick technical check. Its technical checks are broad if shallow, and its Page Analysis tab can replace several full reports a week for writers and editors who work from competitors' articles. Anyone who needs whole-site audits, ranking history or bulk analysis will open the app instead. The panel looks at one page at a time. That is its strength and its limit. If you want Serpstat data inside an AI assistant instead, see our Serpstat MCP guide.

The bottom line

The Website SEO Checker is a useful companion to a Serpstat Team plan, at its best for quick keyword gap checks on competitors' pages. Install it from your browser's store, paste a Team token, open a competitor's best article and read Page Analysis. If the missing keywords surprise you, the extension has earned its place in your toolbar. If you are on Freemium, test whether your token returns data before you build a habit around it.