2,328,232 URLs crawled
The free SEO checker for any webpage
Purpose-built for any webpage
The browser-based SEO checker thousands of developers, agencies, and SEO pros use to audit websites every week. 30+ on-page checks — title tags, meta, headings, schema, accessibility, and Core Web Vitals — in seconds. No account, no email, no upsell.
On-page SEO, the whole picture.
One free tool covering everything a search engine — and an AI agent — checks for.
30+ on-page checks
Title tags, meta, headings, images, links, canonicals and more — over 30 checks per page.
Core Web Vitals
Real Lighthouse performance, LCP, CLS and accessibility scores for any URL.
Structured data
Validate schema, Open Graph and Twitter cards so search and social render you right.
AI readiness
Score how citable a page is for ChatGPT, Claude and Google AI Overviews.
No sign-up
No account, no email, no daily limit. Paste a URL and go.
Runs in your browser
Analysis runs client-side — your data never leaves your session.
Bulk auditing
Check up to 20 URLs at once and export the results to CSV.
Instant SEO score
Every audit returns a clear score out of 100 with prioritised fixes.
Purpose-built tools for every SEO job
Beyond the main audit — crawl whole sites, compare pages, check rankings, generate schema, preview SERPs.
Site Audit
Crawl your sitemap.xml and audit up to 30 pages across the whole site.
Run audit →Bulk URL Checker
Paste up to 20 URLs and score them all at once with CSV export.
Check URLs →Broken Link Checker
Scan any page for dead links, 404s, and redirect chains (up to 100 links).
Find broken links →SEO Compare
Side-by-side comparison of two pages across every on-page factor.
Compare pages →SERP Snippet Generator
Preview exactly how your page appears in Google results with pixel-width feedback.
Preview snippet →Redirect Checker
Check HTTP/HTTPS and WWW/non-WWW variants redirect to one canonical URL.
Check redirects →Keyword Rank Checker
Check your Google ranking position for any keyword.
Check ranking →Schema Generator
Create JSON-LD for FAQ, Article, Product, LocalBusiness markup.
Generate schema →Meta Tag Generator
Generate title, description, OG, and Twitter Card tags for any page.
Generate tags →Run a full audit in seconds
Paste a URL. Get a score. Fix issues. No configuration required.
Enter any URL
Drop in a webpage address — Shopify, WordPress, custom builds, any public site. Add HTTP Basic auth for staging or dev sites.
Instant audit
30+ on-page checks run in parallel: meta tags, headings, schema, accessibility, Core Web Vitals, tech stack — all in seconds.
Score + fixes
Get a score out of 100 with specific recommendations for every issue. Download a branded PDF or export CSV for clients.
Everything a crawler sees
30+ on-page signals, grouped the way a developer thinks about them.
Meta tags
- Title tag — presence & length
- Meta description — length
- Canonical URL
- Open Graph & Twitter Card
- Robots directives
Headings & content
- H1 uniqueness
- H1–H6 hierarchy & nesting
- Word count & text-to-HTML ratio
- Flesch–Kincaid readability
- Keyword density
Structured data
- JSON-LD detection
- 15+ Schema.org types
- Required field validation
- FAQ, Article, Product, Recipe…
Images
- Alt text — per image
- Width / height attributes
- Lazy loading (loading="lazy")
- Linked-image alt
Technical & stack
- HTTPS & URL structure
- Script loading (async/defer)
- Accessibility (ARIA, labels)
- 40+ technologies (CMS, frameworks, analytics, CDN)
SEO guides & resources
Free guides covering fundamentals, technical SEO, AI search, and platform-specific optimisation.
Getting started
How-to guides
Technical SEO
The foundation of every ranking
On-page SEO is the foundation of search engine optimisation. While backlinks and domain authority play a role in rankings, search engines need to understand what your page is about before they can rank it.
Proper title tags, meta descriptions, heading structure, and structured data make it easier for Google to crawl, index, and rank your content. On-page issues are the easiest to fix — you have full control, and improvements take effect the moment search engines recrawl.
RankNibbler runs entirely in your browser with no account required, and includes features that many paid tools don't offer — keyword density, readability scoring, tech detection, and accessibility checks. Your page content is never stored.
Built for real SEO workflows
- Website owners — check if your pages follow SEO best practices without needing technical knowledge.
- SEO professionals — audit client pages in seconds and share clear, actionable reports.
- Content writers — verify meta tags, headings, and structure before publishing.
- Web developers — catch missing alt text, render-blocking scripts, and broken structured data.
- Marketing teams — ensure landing pages are optimised before running campaigns.
Frequently asked questions
Is RankNibbler free to use?
Yes, RankNibbler is completely free. There are no sign-ups, no limits, and no premium tiers. Enter any URL and get a full on-page SEO audit instantly.
Does RankNibbler store the pages it analyses?
No. RankNibbler fetches the page in real time, runs the analysis in your browser, and does not store any page content. Your data stays in your browser session and is cleared when you close the tab.
Why is my score low even though my site looks fine?
A visually polished website can still have poor on-page SEO. Common hidden issues include missing meta descriptions, duplicate title tags, missing alt text on images, no structured data, and render-blocking scripts. These are invisible to visitors but affect how search engines understand and rank your pages.
What is a good SEO score?
A score of 80 or above is considered good and means the page follows most SEO best practices. A score of 50–79 means there are several issues worth fixing. Below 50 indicates significant problems that are likely hurting your search rankings. See the full score breakdown for details on how each check contributes to the total.
What is keyword density?
Keyword density is the percentage of times a word appears on a page relative to the total word count. For example, if "shoes" appears 15 times in a 1,000-word article, the keyword density is 1.5%. RankNibbler's keyword density checker extracts the top keywords and phrases so you can see what terms dominate your content.
How do I check my website's SEO?
Enter your URL at the top of this page and click Analyse. RankNibbler will fetch your page and run over 30 checks covering meta tags, headings, images, links, structured data, readability, keyword density, tech stack, accessibility, and more. You will receive a score out of 100 with clear recommendations for every issue found.
What does RankNibbler check?
RankNibbler checks over 30 on-page SEO factors including title tags, meta descriptions, heading structure, image alt text, internal and external links, structured data, Open Graph tags, script loading, canonical URLs, robots directives, word count, text-to-HTML ratio, favicon, HTTPS, URL structure, keyword density, readability score, lazy loading, image dimensions, empty links, nofollow ratio, deprecated HTML, doctype, charset, tech stack detection, accessibility checks, social media links, RSS feeds, and CSS/JS file counts.
How often should I run an SEO audit?
Run an audit whenever you publish or update a page. For existing pages, a monthly check is a good habit to catch any regressions or new issues. If you have made significant site changes such as a redesign, migration, or CMS update, audit your key pages immediately after.
Can RankNibbler check pages behind a login?
Use the HTTP Basic or Storefront Password fields for staging sites and password-protected Shopify stores. For pages behind a full user login, RankNibbler can only analyse publicly accessible pages — it fetches pages the same way a search engine bot would.
How do I fix a missing meta description?
Add a <meta name="description" content="Your description here"> tag inside the <head> section of your HTML. The description should be 120–160 characters, include your target keyword, and give searchers a reason to click. Most CMS platforms like WordPress have SEO plugins that make this easy. Learn more about meta descriptions.
What is structured data and do I need it?
Structured data is code (usually JSON-LD) that tells search engines exactly what your content is about — whether it is a product, article, FAQ, recipe, or business. It enables rich results in Google such as star ratings, FAQ dropdowns, and product prices. While not required, pages with structured data often get more clicks. Use the structured data checker to see what your page has.
What technologies can RankNibbler detect?
RankNibbler identifies over 40 technologies from the HTML source, including CMS platforms (WordPress, Shopify, Squarespace, Wix), JavaScript frameworks (React, Next.js, Vue.js, Angular), analytics tools (Google Analytics, Hotjar, Clarity), CDNs (Cloudflare, CloudFront), SEO plugins (Yoast, Rank Math), and more. See the full list on the tech stack checker page.