Home · Tools

Free SEO tools

The toolkit we use in-house, open to everyone. No disguised freemium, no email required to see results. You paste, you get the answer.

✓ 36 tools✓ No signup✓ No time limit

AI Visibility / GEO

Measure whether your brand is cited in AI answers and spot the sub-questions where you are missing.

Snippets & SERP

Visualize and prep the Google presentation before publishing.

Structured data

Generate and validate Schema.org / JSON-LD markup.

Linking

Audit a backlink profile quality, anchor diversity, internal linking.

Most used

Backlink Anchor Audit

Paste your backlink anchors and measure their diversity: brand, naked URL, exact match, long-tail, generic. Auto-detects over-optimization.

Open the tool

Domain Age & WHOIS

Domain creation date, registrar, nameservers, status. Official RDAP data to evaluate a domain before purchase or before posting a backlink on it.

Open the tool
Most used

Outbound Links Audit

Before buying a backlink on a page, check it's not a link farm. Counts dofollow vs nofollow, internal/external ratio, density per 1000 words, top destinations.

Open the tool

Hidden Text Detector

Before buying a backlink, scan the host page for CSS-hidden links: display:none, visibility:hidden, font-size:0, negative text-indent. Classic PBN pattern.

Open the tool
Most used

Sellable URL, eligibility

Is a URL eligible to receive an editorial backlink? Score 0-100 across 7 axes: indexability, substance, structure, links, brand, cleanliness, freshness.

Open the tool
Most used

Internal Linking Opportunities

Paste a host URL + target keywords: find existing paragraphs that mention your KWs without linking yet. Editorial anchors ready to place.

Open the tool
Most used

Internal PageRank Simulator

Compute your site's internal PageRank from an edge CSV: real hubs, orphan pages, dead-ends, Gini distribution. Configurable damping factor and iterations.

Open the tool
Most used

Backlink Quality Scorer

0-100 authority score of a URL via DataForSEO live: dofollow RD, Link Rank, broken-link ratio. 10 req/day.

Open the tool

Anchor Profile from URL

Fetch real anchors pointing to a URL via DataForSEO + brand/exact/partial/generic classification + Penguin risk score. 10 req/day.

Open the tool

Editorial content

Measure readability, extract metas in bulk, audit what your pages really say.

Technical SEO

Inspect robots, hreflang, canonical, headers, the plumbing that decides indexing.

robots.txt Multi-Bot Tester

Test your robots.txt against 18 user-agents: Googlebot, Bingbot, GPTBot, ClaudeBot, PerplexityBot, Applebot and other AI crawlers. Path × bot matrix.

Open the tool

hreflang Tester

Verify your hreflang tags: valid ISO codes, reciprocity between language versions, x-default, conformance with Google's recommendations.

Open the tool

HTTP Headers SEO Checker

Inspect HTTP response headers: x-robots-tag, cache-control, HSTS, link, vary, server. SEO + security annotations on impactful headers.

Open the tool

sitemap.xml Validator

Validate your sitemap.xml: structure, URL count, lastmod outliers, sitemap-index recursion. Conforms to sitemaps.org and Google.

Open the tool
Most used

Bulk Status Code Checker

Test up to 200 URLs at once: HTTP code, redirect chain, response time. Ideal for backlink profile audits.

Open the tool

Canonical Chain Checker

Audit a URL's canonical tags: self-canonical, canonical chain, HTML vs HTTP header conflict, loop detection.

Open the tool

HTTPS Mixed Content Checker

Detect HTTP resources served on an HTTPS page: images, scripts, iframes, fonts. Silent cause of "not secure" warnings and user-trust loss.

Open the tool

Heavy Resources Detector

Detect images, scripts, videos and CSS files over 2 MB on a page, the resources Google struggles to crawl and that wreck your crawl budget.

Open the tool
Most used

Indexability Verdict

One URL, one verdict: indexable or not, and if not, why exactly. Combines HTTP status, robots.txt, meta robots, X-Robots-Tag, canonical chain and hreflang into a single check.

Open the tool

Googlebot vs Chrome Diff

Compare what Googlebot sees vs a regular browser. Detects cloaking, JS-only renders, and content served differently by user-agent.

Open the tool

Soft 404 Detector

A page returns 200 but displays "page not found"? Soft 404s fool standard tools but wreck your indexing. This tool hunts them explicitly.

Open the tool

TTFB, Protocol & Compression

Three perf measures in one check: server Time To First Byte, HTTP version (1.1 / 2 / 3), Brotli or gzip compression detected. Quick sniper to flag a slow or misconfigured server.

Open the tool

Lazy-Load Above the Fold

Detects <code>loading="lazy"</code> images visible immediately on screen. Silent LCP killer, Google penalizes mechanically.

Open the tool

Core Web Vitals Checker

LCP, INP, CLS + Lighthouse score for any URL via Google PSI API. Mobile vs desktop choice.

Open the tool

More tools coming

AI bot robots.txt tester, hreflang validator, internal linking audit, PageRank simulator, backlink quality scorer. The public roadmap is on GitHub.

See the roadmap

Beyond the tools?

Nautilinks is a network of publisher sites selling backlinks direct. Public catalog, publisher pricing shown, no commission, no opaque marketplace.

See the network See pricing