How to Tell If a Website Uses Yoast SEO
Yoast SEO is the most popular WordPress SEO plugin. Detect it via its HTML comments, the /wp-content/plugins/wordpress-seo/ assets and the Yoast schema graph it outputs.
Yoast SEO is the most widely used SEO plugin for WordPress, managing on-page SEO — titles, meta descriptions, structured data, XML sitemaps and social tags — for a huge share of WordPress sites. Because it leaves an unmistakable comment block in the page head, detecting it is trivial: view the source and look for the "optimized with the Yoast SEO plugin" comment. This guide covers every reliable signal, the markup it generates, the look-alikes to rule out, and what Yoast usage tells you about the site.
What is Yoast SEO?
Yoast SEO is a WordPress plugin that handles the technical and on-page aspects of search-engine optimisation so site owners do not have to edit theme code. It manages the page <title> and meta description, generates structured data (schema.org JSON-LD), outputs Open Graph and Twitter Card tags for social sharing, produces and maintains the XML sitemap, controls canonical URLs and robots directives, and offers editorial guidance (the famous traffic-light readability and keyword analysis in the WordPress editor). It is the market leader in WordPress SEO, with All in One SEO and the newer Rank Math as its main rivals.
For detection, the key context is twofold: Yoast is a WordPress plugin, so finding it confirms WordPress; and its presence indicates a site that actively manages on-page SEO with the leading tool rather than leaving it to chance. Because Yoast wraps the meta tags it manages in a clearly-labelled comment block and outputs a recognisable schema graph, it is one of the easiest plugins to confirm from the page source. Its presence signals an owner who cares about search visibility.
How Yoast appears in the page
Yoast's signature is a comment block in the <head> that wraps the tags it manages: it opens with <!-- This site is optimized with the Yoast SEO plugin - https://yoast.com/wordpress/plugins/seo/ --> and closes with <!-- / Yoast SEO plugin. -->. Between them sit the meta description, canonical, Open Graph and Twitter tags, and the structured-data graph: a <script type="application/ld+json"> containing an @graph array that links entities (WebSite, WebPage, Organization or Person, BreadcrumbList, Article) via @id references in Yoast's characteristic pattern. Premium Yoast adds further blocks.
Beyond the head, Yoast's assets load from /wp-content/plugins/wordpress-seo/ (its plugin folder name, a historical artefact of the plugin's original name). It also exposes the XML sitemap at /sitemap_index.xml. So a Yoast site shows the comment block, the @graph schema, the wordpress-seo asset path, and the Yoast sitemap. Knowing these — the comment block, the schema graph, and the wordpress-seo plugin path — makes detection instant.
How to tell if a website uses Yoast SEO
Confirm at least one strong signal (the comment block suffices).
1. View the page source. Search the <head> for Yoast SEO plugin. The opening and closing comment block is the definitive signal.
2. Inspect the schema graph. Look for a JSON-LD @graph with Yoast-style @id references linking WebSite, WebPage, Organization/Person and BreadcrumbList.
3. Check asset paths. Look for assets from /wp-content/plugins/wordpress-seo/.
4. Check the sitemap. Visit /sitemap_index.xml — Yoast's sitemap has a recognisable structure attributing itself to Yoast.
5. Confirm WordPress. Because Yoast is a WordPress plugin, the site will show WordPress signals (/wp-content/, /wp-includes/).
What the Yoast signals look like
<!-- This site is optimized with the Yoast SEO plugin v22.0 - https://yoast.com/wordpress/plugins/seo/ -->
<meta name="description" content="..." />
<script type="application/ld+json" class="yoast-schema-graph">{"@context":"https://schema.org","@graph":[{"@type":"WebSite","@id":"…/#website"}, …]}</script>
<!-- / Yoast SEO plugin. -->
GET /wp-content/plugins/wordpress-seo/...
The "optimized with the Yoast SEO plugin" comment block and the @graph schema are conclusive.
Yoast versus other SEO plugins — avoiding false positives
Match the comment and asset path to keep WordPress SEO plugins distinct. Yoast uses the "optimized with the Yoast SEO plugin" comment and /wp-content/plugins/wordpress-seo/; Rank Math uses <!-- Rank Math WordPress SEO plugin --> and /wp-content/plugins/seo-by-rank-math/; All in One SEO (AIOSEO) uses its own comment and aioseo assets; The SEO Framework uses a different marker. The Yoast comment text and the wordpress-seo folder name are unique to Yoast. A site can only run one primary SEO plugin at a time (running two causes conflicts), so the comment block reliably identifies which one. Note the folder is wordpress-seo, not yoast, a common point of confusion.
How reliable is each Yoast signal?
The "optimized with the Yoast SEO plugin" comment block is definitive and reveals the version. The Yoast @graph schema is equally strong. The /wp-content/plugins/wordpress-seo/ asset path corroborates. The Yoast sitemap at /sitemap_index.xml is supporting evidence. The WordPress context reliably accompanies Yoast. There is essentially no false-positive risk once you see the comment block. As a rule, viewing the source for the Yoast comment settles it immediately, and the version in the comment indicates how current the plugin is.
What Yoast usage reveals about a site
Finding Yoast SEO signals a WordPress site that actively manages on-page SEO with the leading tool. Its presence tells you the owner (or their agency) cares about search visibility and has set up titles, descriptions, schema, sitemaps and social tags deliberately. The Yoast version indicates how well-maintained the site is (an old version suggests neglect; a current one suggests active care), and Yoast Premium features (additional schema, redirect manager) indicate a paid, more serious SEO setup. If you sell SEO, content, or WordPress services, a Yoast site marks an owner already invested in SEO — receptive to doing more, or to migrating to a more capable setup. Because Yoast is so dominant, its presence is common, but the version and premium status add useful nuance about the site's SEO maturity.
What finding Yoast means for sales, agencies and competitive research
For sales and prospecting, Yoast marks a WordPress owner who invests in SEO — a fit for SEO tools, content services, and WordPress maintenance. The version and premium status hint at how serious and current their SEO effort is.
For agencies and consultants, finding Yoast tells you the client manages on-page SEO, so engagements can focus on advanced SEO (technical, content, schema), or on migrating from a dated Yoast setup to a better-configured one. An old Yoast version is a maintenance talking point.
For competitive and market research, Yoast versus Rank Math versus AIOSEO adoption maps the WordPress SEO-plugin landscape, and a competitor's choice and version hint at their SEO sophistication.
Yoast in the wider WordPress stack
Yoast sits in the SEO layer of a WordPress stack. It accompanies the usual WordPress components — a theme, a page builder (often Elementor or Gutenberg), a caching plugin (WP Rocket), a forms plugin (Contact Form 7 or WPForms), and analytics (GA4, often via a plugin). On content sites it pairs with editorial workflows; on ecommerce (WooCommerce) it manages product and category SEO. For an auditor, the valuable details are the Yoast version, whether Premium features appear, the schema types output, and the surrounding WordPress stack (theme, builder, caching, analytics); together these reveal a WordPress site's SEO maturity and how actively it is maintained. Across a market, the Yoast-versus-Rank-Math-versus-AIOSEO split, read from these comment blocks, is a quick way to map how WordPress sites in a sector approach SEO and which tools are winning — useful trend data for anyone building, selling to, or competing within the WordPress ecosystem.
A quick Yoast confirmation walkthrough
Open the site and view the page source (Ctrl+U / Cmd+Option+U). Search for Yoast SEO plugin — you should find the opening comment <!-- This site is optimized with the Yoast SEO plugin ... --> and the closing <!-- / Yoast SEO plugin. -->, wrapping the meta tags and the @graph JSON-LD. Note the version in the comment. Optionally check /wp-content/plugins/wordpress-seo/ assets and /sitemap_index.xml. The Yoast comment block is enough to confirm Yoast SEO and its version.
A quick Yoast detection checklist
- View source and search for the "optimized with the Yoast SEO plugin" comment — conclusive.
- Look for the Yoast
@graphJSON-LD schema block. - Check assets under
/wp-content/plugins/wordpress-seo/. - Visit
/sitemap_index.xmlfor the Yoast sitemap. - Note the version in the comment to gauge maintenance.
- Distinguish Yoast from Rank Math (
seo-by-rank-math) and AIOSEO via the comment text.
Detecting Yoast at scale
Checking one site is quick, but mapping SEO-plugin adoption across many WordPress domains — to find SEO-invested owners or dated installs — calls for automation. StackOptic detects Yoast SEO and thousands of other technologies from a real browser, reading the head markup, schema and plugin assets. For related reading, see our guides to identifying a WordPress theme and its plugins and what schema markup is and which types you need, and the full Yoast SEO technology profile.
Frequently asked questions
What is the fastest way to tell if a site uses Yoast SEO?
View the page source and look in the <head> for the comment block that begins '<!-- This site is optimized with the Yoast SEO plugin' and ends '<!-- / Yoast SEO plugin. -->'. That comment, wrapping the meta tags Yoast manages, is the definitive signal.
What does the Yoast schema graph look like?
Yoast outputs a JSON-LD structured-data block with an @graph array linking entities (WebSite, WebPage, Organization/Person, BreadcrumbList, Article) via @id references in a characteristic Yoast pattern. Finding this @graph structure, alongside the Yoast comment, confirms Yoast SEO.
Does Yoast mean the site uses WordPress?
Yes. Yoast SEO is a WordPress plugin, so finding it means the site runs WordPress. It is therefore also a reliable indicator that WordPress is in the stack, which you can confirm via /wp-content/ and /wp-includes/ paths.
How can I tell Yoast from Rank Math or All in One SEO?
Each leaves distinct comments and asset paths: Yoast uses 'This site is optimized with the Yoast SEO plugin' and /wp-content/plugins/wordpress-seo/; Rank Math uses '<!-- Rank Math WordPress SEO plugin -->' and seo-by-rank-math; All in One SEO uses its own comment and aioseo assets. The comment text is the quickest discriminator.
What does it mean if a site uses Yoast SEO?
Yoast SEO is the most popular WordPress SEO plugin. Finding it signals a WordPress site whose owner actively manages on-page SEO — titles, meta descriptions, schema, sitemaps, social tags — with the market-leading tool, indicating attention to search visibility.
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