30 SEO Bookmarklets Every SEO Person Should Have
If you’ve ever needed a quick SEO check mid-audit but didn’t want to install another browser extension or wait for a tool to load, you already understand the value of speed. SEO bookmarklets are tiny JavaScript snippets that run instantly in your browser—no plugins, no API calls, no third-party trackers.
They’re especially useful for technical SEO audits, on-page reviews, quick client demos, and content diagnostics. Unlike extensions that consume memory or require permissions, bookmarklets are passive until you click them. They work across all modern browsers and don’t require updates or maintenance.
In this article, you’ll find 30 battle-tested SEO bookmarklets that cover everything from meta tag validation and heading analysis to structured data checks and performance diagnostics. Each bookmarklet includes the code, an explanation of what it does, and real-world scenarios where it’s most useful.
Whether you’re an SEO analyst, technical SEO specialist, content writer, or web developer handling SEO tasks, these bookmarklets will save you hours during audits and content reviews.
How to Use SEO Bookmarklets
Using bookmarklets is straightforward:
- Create a new bookmark in your browser (right-click the bookmarks bar and select “Add page” or “New bookmark”)
- Give it a descriptive name (e.g., “Check Meta Description”)
- Paste the JavaScript code into the URL/location field
- Save the bookmark
- Click the bookmark when you’re on any webpage to run it
That’s it. The bookmarklet executes immediately and shows results in an alert, highlights elements on the page, or opens a new tab with diagnostic tools.
30 Essential SEO Bookmarklets
On-Page SEO
These bookmarklets help you validate critical on-page SEO elements during content audits and quality reviews.
1. Show Meta Title & Description
What It Does:
Displays the page’s title tag and meta description in a quick alert dialog.
Why It’s Useful for SEO:
Title tags and meta descriptions are the first elements users see in search results. This bookmarklet lets content writers and SEO auditors verify these fields instantly without opening DevTools or viewing the page source.
Bookmarklet Code:
javascript:(function(){alert("Title: "+document.title+"\n\nMeta Description: "+(document.querySelector('meta[name="description"]')?.content||"Not Found"));})();Example Use Case:
Perfect for quick SERP snippet previews during content reviews or client calls.
2. Meta Robots Checker
What It Does:
Checks if the page has a meta robots tag and displays its content (e.g., noindex, nofollow).
Why It’s Useful for SEO:
Technical SEOs need to verify indexability directives quickly. This bookmarklet helps you catch accidental noindex tags on pages that should be indexed, or confirm that staging pages are properly blocked.
Bookmarklet Code:
javascript:(function(){alert(document.querySelector('meta[name="robots"]')?.content||"No meta robots tag found");})();Example Use Case:
Essential during pre-launch site audits to avoid indexation disasters.
3. Canonical URL Checker
What It Does:
Displays the canonical URL specified in the page’s <link rel="canonical"> tag.
Why It’s Useful for SEO:
Canonical tags prevent duplicate content issues. SEO professionals use this bookmarklet to verify that pagination, filtered pages, or parameter-heavy URLs point to the correct canonical version.
Bookmarklet Code:
javascript:(function(){alert(document.querySelector('link[rel="canonical"]')?.href||"No canonical tag found");})();Example Use Case:
Quickly audit category pages, product variations, or AMP/mobile pages for correct canonicalization.
4. H1–H6 Outline Viewer
What It Does:
Extracts all heading tags (H1 through H6) and displays them in hierarchical order.
Why It’s Useful for SEO:
Proper heading structure improves content accessibility and helps search engines understand page hierarchy. Content SEOs and auditors use this to check if headings follow a logical, semantic structure.
Bookmarklet Code:
javascript:(function(){let o="";document.querySelectorAll("h1,h2,h3,h4,h5,h6").forEach(h=>o+=h.tagName+": "+h.innerText+"\n");alert(o||"No headings found");})();Example Use Case:
Useful when analyzing competitor content or auditing blog posts for semantic organization.
5. Multiple H1 Detector
What It Does:
Counts the number of H1 tags on the page.
Why It’s Useful for SEO:
While modern HTML5 allows multiple H1s in different sections, most SEO best practices recommend a single, unique H1 per page. This bookmarklet helps you enforce that rule during content reviews.
Bookmarklet Code:
javascript:(function(){alert("H1 count: "+document.querySelectorAll("h1").length);})();Example Use Case:
Great for quick on-page SEO audits or when reviewing developer-built templates.
Image & Media SEO
Images are often overlooked in SEO audits. These bookmarklets help you catch common accessibility and optimization issues.
6. Images Missing ALT Text
What It Does:
Counts how many images on the page are missing alt attributes.
Why It’s Useful for SEO:
Alt text is essential for image SEO and accessibility. Content writers and auditors use this to identify images that need descriptive alt attributes before publishing.
Bookmarklet Code:
javascript:(function(){let imgs=[...document.images].filter(i=>!i.alt);alert("Images missing ALT: "+imgs.length);})();Example Use Case:
Essential during final pre-publish content checks and accessibility audits.
7. Largest Image Finder
What It Does:
Identifies the largest image on the page by pixel dimensions.
Why It’s Useful for SEO:
Large images can slow down page load times, affecting Core Web Vitals. Technical SEOs use this to find images that need compression or lazy loading.
Bookmarklet Code:
javascript:(function(){let max=[...document.images].sort((a,b)=>b.naturalWidth*b.naturalHeight-a.naturalWidth*a.naturalHeight)[0];alert(max?max.src:"No images");})();Example Use Case:
Perfect for performance audits and LCP (Largest Contentful Paint) optimization.
Links & Structure
Link analysis is critical for internal linking strategies and outbound link audits.
8. Count Internal vs External Links
What It Does:
Counts the number of internal links (same domain) and external links (different domains) on the page.
Why It’s Useful for SEO:
SEO strategists use this to analyze internal linking patterns and ensure pages aren’t leaking too much link equity through excessive external links.
Bookmarklet Code:
javascript:(function(){let i=0,e=0;document.querySelectorAll("a[href]").forEach(a=>a.href.includes(location.hostname)?i++:e++);alert("Internal: "+i+"\nExternal: "+e);})();Example Use Case:
Ideal for content audits and internal linking optimization projects.
9. Highlight NoFollow Links
What It Does:
Highlights all links with rel="nofollow" in yellow on the page.
Why It’s Useful for SEO:
Technical SEOs use this to verify that sponsored, user-generated, or untrusted links include proper nofollow attributes to comply with Google’s guidelines.
Bookmarklet Code:
javascript:(function(){document.querySelectorAll('a[rel*="nofollow"]').forEach(a=>a.style.background="yellow");})();Example Use Case:
Quick visual audit for affiliate sites, guest posts, or UGC-heavy pages.
10. Broken Anchor Detector
What It Does:
Counts the number of <a> tags without an href attribute.
Why It’s Useful for SEO:
Broken or empty anchor tags create poor UX and can indicate sloppy development. SEO auditors use this to catch broken links before they impact crawl efficiency.
Bookmarklet Code:
javascript:(function(){let b=[...document.querySelectorAll("a")].filter(a=>!a.href);alert("Broken anchors: "+b.length);})();Example Use Case:
Useful during site migrations, redesigns, or CMS transitions.
Content & UX
Content quality directly impacts rankings. These bookmarklets help you analyze readability and keyword usage.
11. Word Count
What It Does:
Counts the total number of words in the page’s body text.
Why It’s Useful for SEO:
Content SEOs use word count as a rough benchmark against competitor pages. It’s also useful for verifying minimum content length requirements.
Bookmarklet Code:
javascript:(function(){alert("Word Count: "+document.body.innerText.trim().split(/\s+/).length);})();Example Use Case:
Great for quick content brief validations or comparing competitor article lengths.
12. Keyword Density Prompt
What It Does:
Prompts you to enter a keyword, then counts how many times it appears on the page.
Why It’s Useful for SEO:
While keyword stuffing is penalized, understanding keyword frequency helps content writers maintain natural usage. This bookmarklet provides quick density checks during content optimization.
Bookmarklet Code:
javascript:(function(){let k=prompt("Keyword?");if(!k)return;let t=document.body.innerText.toLowerCase();alert((t.match(new RegExp(k.toLowerCase(),"g"))||[]).length+" occurrences");})();Example Use Case:
Perfect for on-page optimization reviews and content rewrites.
13. Readability (Avg Sentence Length)
What It Does:
Calculates the average number of words per sentence on the page.
Why It’s Useful for SEO:
Readability affects user engagement and dwell time. Content SEOs use this metric to identify overly complex or poorly structured content.
Bookmarklet Code:
javascript:(function(){let t=document.body.innerText;alert("Avg words/sentence: "+(t.split(/\./).join("").split(/\s+/).length/(t.split('.').length||1)).toFixed(2));})();Example Use Case:
Useful during content quality audits and readability optimization projects.
Technical SEO
Technical SEO bookmarklets help you diagnose indexation, security, and protocol issues.
14. Page Indexability Test
What It Does:
Checks if the page has a noindex directive in the meta robots tag.
Why It’s Useful for SEO:
Technical SEOs use this for rapid indexability checks during site launches or migrations to prevent accidental de-indexing.
Bookmarklet Code:
javascript:(function(){alert(document.querySelector('meta[name="robots"]')?.content.includes("noindex")?"NOINDEX":"Indexable");})();Example Use Case:
Critical during staging-to-production transitions and post-launch audits.
15. HTTPS Check
What It Does:
Verifies if the page is served over HTTPS.
Why It’s Useful for SEO:
HTTPS is a ranking signal. Technical SEOs use this to quickly verify secure connections, especially after SSL certificate installations.
Bookmarklet Code:
javascript:(function(){alert(location.protocol==="https:"?"HTTPS OK":"NOT HTTPS");})();Example Use Case:
Essential during site security audits and SSL migration projects.
16. View HTTP Headers (via Redirect)
What It Does:
Opens a third-party HTTP header checker tool with the current page URL pre-filled.
Why It’s Useful for SEO:
HTTP headers reveal server-side SEO configurations like redirects, cache control, and server types. Technical SEOs use this for advanced diagnostics.
Bookmarklet Code:
javascript:(function(){window.open("https://httpstatus.io/?url="+encodeURIComponent(location.href));})();Example Use Case:
Great for debugging redirect chains, server errors, and caching issues.
17. View Source Instantly
What It Does:
Opens the page’s raw HTML source in a new tab.
Why It’s Useful for SEO:
Viewing source is faster than opening DevTools. Technical SEOs use this to inspect rendered HTML, server-side scripts, or hidden elements.
Bookmarklet Code:
javascript:(function(){window.open("view-source:"+location.href);})();Example Use Case:
Quick access during code reviews or when verifying JavaScript-rendered content.
International & Structured Data
Multilingual sites and rich results require specialized checks.
18. Hreflang Checker
What It Does:
Displays all hreflang tags on the page, showing language and region codes with their target URLs.
Why It’s Useful for SEO:
International SEOs use this to verify correct hreflang implementation on multilingual or multi-regional sites to avoid duplicate content issues across languages.
Bookmarklet Code:
javascript:(function(){let h=[...document.querySelectorAll('link[rel="alternate"][hreflang]')].map(x=>x.hreflang+" → "+x.href).join("\n");alert(h||"No hreflang found");})();Example Use Case:
Critical for auditing global e-commerce sites or international content hubs.
19. Structured Data Test
What It Does:
Opens Google’s Rich Results Test tool with the current page URL pre-filled.
Why It’s Useful for SEO:
Structured data enables rich snippets in search results. SEO specialists use this to validate schema markup for products, recipes, articles, and events.
Bookmarklet Code:
javascript:(function(){window.open("https://search.google.com/test/rich-results?url="+encodeURIComponent(location.href));})();Example Use Case:
Essential after implementing Schema.org markup or when troubleshooting rich result disappearances.
20. Open Graph Preview
What It Does:
Displays all Open Graph meta tags used for social media sharing previews.
Why It’s Useful for SEO:
Social signals indirectly impact SEO. Content marketers and SEO professionals use this to verify Facebook, LinkedIn, and other social media preview data.
Bookmarklet Code:
javascript:(function(){let o="";document.querySelectorAll('meta[property^="og:"]').forEach(m=>o+=m.property+": "+m.content+"\n");alert(o||"No OG tags");})();Example Use Case:
Perfect before sharing content on social platforms or during social media optimization audits.
Performance & Core Web Vitals
Page speed is a confirmed ranking factor. These bookmarklets help you diagnose performance issues.
21. Lighthouse Quick Launch
What It Does:
Opens Google PageSpeed Insights with the current page URL pre-filled.
Why It’s Useful for SEO:
PageSpeed Insights provides Core Web Vitals data, which directly impact rankings. Technical SEOs use this for on-demand performance audits.
Bookmarklet Code:
javascript:(function(){window.open("https://pagespeed.web.dev/report?url="+encodeURIComponent(location.href));})();Example Use Case:
Essential during performance optimization projects and Core Web Vitals troubleshooting.
22. Page Load Time (Navigation API)
What It Does:
Shows the page’s total load time in milliseconds using the Navigation Timing API.
Why It’s Useful for SEO:
Fast load times improve user experience and rankings. Technical SEOs use this for quick performance checks during audits.
Bookmarklet Code:
javascript:(function(){alert("Load time: "+(performance.timing.loadEventEnd-performance.timing.navigationStart)+" ms");})();Example Use Case:
Great for before/after performance comparisons during optimization work.
Diagnostics & Security
Security and JavaScript errors can impact SEO performance.
23. JavaScript Errors Detector
What It Does:
Reminds you to check the browser console for JavaScript errors.
Why It’s Useful for SEO:
JS errors can break navigation, forms, or tracking. Technical SEOs use this as a reminder to check console logs during audits.
Bookmarklet Code:
javascript:(function(){alert("Open DevTools → Console for JS errors");})();Example Use Case:
Useful during site QA and when troubleshooting broken functionality.
24. Mixed Content Check
What It Does:
Counts the number of insecure resources (loaded over HTTP) on an HTTPS page.
Why It’s Useful for SEO:
Mixed content warnings damage user trust and can break HTTPS benefits. Technical SEOs use this to identify insecure images, scripts, or stylesheets.
Bookmarklet Code:
javascript:(function(){alert([...document.querySelectorAll("img[src^='http:'],script[src^='http:'],link[href^='http:']")).length+" insecure resources");})();Example Use Case:
Critical after migrating a site from HTTP to HTTPS.
Search & Indexing
These bookmarklets help you check how search engines see your site.
25. Google Cache Check
What It Does:
Opens Google’s cached version of the current page.
Why It’s Useful for SEO:
Checking Google’s cache shows the last time Googlebot crawled the page and what version it saw. Technical SEOs use this to verify recent updates have been indexed.
Bookmarklet Code:
javascript:(function(){window.open("https://www.google.com/search?q=cache:"+location.href);})();Example Use Case:
Perfect for verifying that content changes have been picked up by Google.
26. Google Indexed Pages (site:)
What It Does:
Opens a Google search with site:yourdomain.com to show all indexed pages from the current domain.
Why It’s Useful for SEO:
The site: operator helps SEO auditors estimate indexation levels and discover orphaned or unwanted indexed pages.
Bookmarklet Code:
javascript:(function(){window.open("https://www.google.com/search?q=site:"+location.hostname);})();Example Use Case:
Great for quick indexation audits and discovering duplicate content issues.
27. Bing Indexed Pages
What It Does:
Opens a Bing search with site:yourdomain.com to show all indexed pages from the current domain.
Why It’s Useful for SEO:
Bing often indexes different pages than Google. SEO professionals use this to compare indexation across search engines.
Bookmarklet Code:
javascript:(function(){window.open("https://www.bing.com/search?q=site:"+location.hostname);})();Example Use Case:
Useful for multi-engine SEO strategies and indexation discrepancy analysis.
Advanced / Power User
These bookmarklets are for advanced technical audits and debugging.
28. Highlight All Schema Markup
What It Does:
Highlights all elements with itemscope attributes (indicating schema.org microdata) with a red outline.
Why It’s Useful for SEO:
Technical SEOs use this to quickly identify which page sections have structured data markup for visual validation.
Bookmarklet Code:
javascript:(function(){document.querySelectorAll('[itemscope]').forEach(e=>e.style.outline="2px solid red");})();Example Use Case:
Perfect for verifying local business schema, product markup, or article schema implementations.
29. Check Mobile-Friendly Test
What It Does:
Opens Google’s Mobile-Friendly Test tool with the current page URL pre-filled.
Why It’s Useful for SEO:
Mobile-first indexing means mobile usability is critical. Technical SEOs use this to verify responsive design and mobile compatibility.
Bookmarklet Code:
javascript:(function(){window.open("https://search.google.com/test/mobile-friendly?url="+encodeURIComponent(location.href));})();Example Use Case:
Essential during responsive design audits and mobile optimization projects.
30. Extract All URLs from Page
What It Does:
Extracts every link URL on the page and displays them in a prompt dialog for easy copying.
Why It’s Useful for SEO:
Link analysis and extraction is common in SEO audits. Technical SEOs use this to quickly export all URLs for further analysis in spreadsheets or crawl tools.
Bookmarklet Code:
javascript:(function(){prompt("All URLs:",[...document.links].map(l=>l.href).join("\n"));})();Example Use Case:
Great for competitor link analysis, sitemap validation, or internal linking audits.
Conclusion
SEO bookmarklets are underrated productivity tools that every SEO professional should have in their toolkit. Unlike browser extensions that run constantly in the background, bookmarklets are passive, privacy-friendly, and execute only when you need them.
These 30 bookmarklets cover the essential SEO diagnostics you need for on-page audits, technical reviews, content optimization, and indexation monitoring. They’re especially valuable during client calls, quick site reviews, or when you need instant answers without opening heavyweight SEO platforms.
Save these bookmarklets to your browser’s favorites bar and organize them into folders by category (On-Page, Technical, Performance, etc.). Over time, you’ll build a personal SEO toolkit that saves hours during audits and content reviews.
These bookmarklets can save hours during audits and content reviews—start building your personal SEO toolkit today.
Frequently Asked Questions
Are SEO bookmarklets safe?
Yes. Bookmarklets run entirely in your browser and don’t send data to external servers (except those that explicitly open third-party tools like PageSpeed Insights). Always review the JavaScript code before saving a bookmarklet to ensure it’s safe.
Do bookmarklets work on all browsers?
Most bookmarklets work on Chrome, Firefox, Edge, Safari, and other modern browsers. However, some browsers restrict JavaScript execution in bookmarks for security reasons. If a bookmarklet doesn’t work, try it in a different browser or check your browser’s security settings.
Can bookmarklets replace SEO tools?
No. Bookmarklets are designed for quick, on-the-fly diagnostics—not comprehensive crawls or deep analysis. They complement full SEO platforms like Screaming Frog, Ahrefs, or Semrush by providing instant checks without leaving the page you’re auditing.
