Free website tools
Quick, focused checks for one thing at a time. Each runs in seconds with the same engine as our full audit, which checks all of them at once.
Popular:Security Headers CheckerSSL Certificate CheckerCore Web Vitals CheckerMobile-Friendly TestIs It Down? Website Down Checker
Security Headers Checker
Test HSTS, Content-Security-Policy, clickjacking protection and other HTTP security headers, and get an A+ to F grade with exact fixes.
Security · Open tool →SSL Certificate Checker
Check certificate validity, days to expiry, hostname match, TLS version, key strength and the HTTP to HTTPS redirect for any domain.
Security · Open tool →Core Web Vitals Checker
Measure LCP, CLS, INP and the Lighthouse performance score for any URL, with real-user Chrome data when your page has enough traffic.
Performance · Open tool →Redirect Checker
Trace every redirect hop with its status code, spot long chains, temporary redirects and HTTPS downgrades, and test http:// and www variants.
Technical SEO · Open tool →Robots.txt Validator
Check that robots.txt is reachable, find rules that block your whole site or its CSS and JS, and see which AI crawlers you allow.
Technical SEO · Open tool →XML Sitemap Validator
Find your XML sitemap via robots.txt or /sitemap.xml, check it parses, count URLs, review lastmod and confirm the home page is listed.
Technical SEO · Open tool →llms.txt Checker
Check whether your domain publishes an /llms.txt file and serves it as plain text, and learn what the proposal can and cannot do.
Technical SEO · Open tool →Structured Data (Schema) Checker
Find JSON-LD, Microdata and RDFa on a page, list the schema.org types and check the required properties for rich-result types.
Technical SEO · Open tool →Open Graph Preview
See how your link looks when shared and in a Google result, and check og:title, og:description, og:image, og:url and X card tags.
Social · Open tool →Mixed Content Checker
Find http:// scripts, styles, images and iframes on an HTTPS page, forms that post to http:// and password fields on insecure pages.
Security · Open tool →Compression & HTTP/2 Checker
Check whether your HTML is served with Brotli or gzip, whether the server speaks HTTP/2 or HTTP/3, and how fast the first byte arrives.
Performance · Open tool →Email Security Checker (SPF, DKIM, DMARC)
Check MX, SPF and its 10-lookup limit, DKIM on common selectors, DMARC policy and reporting, MTA-STS and TLS-RPT for any domain.
Security · Open tool →Mobile-Friendly Test
Check the viewport tag, mobile Lighthouse performance and accessibility, page weight and intrusive prompts, and see a phone screenshot.
Performance · Open tool →Is It Down? Website Down Checker
Check whether a website is up right now from our server in Germany: status code, response times, redirects and the exact reason when it fails.
Performance · Open tool →HTTP Headers Checker
List every HTTP response header a page sends, with cookies shown by name, plus compression, HTTP version, server disclosure and CORS checks.
Security · Open tool →AI Crawler Checker
See which AI crawlers your robots.txt allows: AI search crawlers, user-triggered fetchers and training bots such as GPTBot, ClaudeBot and CCBot.
Technical SEO · Open tool →WordPress Theme & Plugin Detector
Find out whether a site runs WordPress, which theme and plugins its page loads, their visible versions, and whether any look outdated.
Technical SEO · Open tool →Schema Markup Generator
Build JSON-LD structured data for Organization, LocalBusiness, Article, FAQPage and Product from a simple form, ready to paste into your page.
Technical SEO · Open tool →Open Graph & Twitter Card Generator
Generate og:title, og:description, og:image, og:url and Twitter card meta tags for a page, ready to paste into the head of your HTML.
Social · Open tool →Robots.txt Generator
Create a robots.txt with allow and disallow rules, sitemap lines and an option to opt out of AI training crawlers while staying in search.
Technical SEO · Open tool →Security Headers Generator
Generate HSTS, CSP, X-Frame-Options, nosniff, Referrer-Policy, Permissions-Policy and COOP for nginx, Apache or a _headers file.
Security · Open tool →SPF & DMARC Record Generator
Build an SPF record from common email providers within the 10-lookup limit, plus a DMARC record with your policy and reporting address.
Security · Open tool →Domain Age Checker
See when a domain was registered, how old it is, when it expires and which registrar holds it, from public RDAP registry data.
Technical SEO · Open tool →Subdomain Finder
Count the subdomains on a domain's unexpired TLS certificates from public Certificate Transparency logs; verified owners see the full list.
Security · Open tool →Readability Checker
Score a page's text with Flesch Reading Ease and see the average sentence length, the share of long sentences and the word count.
Technical SEO · Open tool →Keyword Density Checker
See the most frequent words and two-word phrases on a page, their density, and whether they appear in the title, description and H1.
Technical SEO · Open tool →Email Address Validator
Check that an email address is well-formed and that its domain can receive mail: MX records, null MX and the A/AAAA fallback.
Security · Open tool →SSL Certificate Decoder
Paste a PEM certificate or chain to read its subject, issuer, SANs, validity dates, key type, SHA-256 fingerprint and chain order.
Security · Open tool →CSR Generator (OpenSSL Command)
Build the OpenSSL command that creates a private key and a CSR with the right subject and SANs on your own server. The key never leaves it.
Security · Open tool →Disavow File Generator
Turn a list of URLs and domains into a correctly formatted disavow.txt for Google Search Console: deduplicated, sorted, with comments.
Technical SEO · Open tool →Hreflang Checker
Check the hreflang tags of a page: valid language and region codes, duplicates, absolute URLs, the self-reference, html lang and the canonical.
Technical SEO · Open tool →Canonical Tag Checker
Check the canonical tag of a page: present, absolute, on HTTPS and the same host, agreeing with og:url, and free of noindex and redirect conflicts.
Technical SEO · Open tool →SERP Snippet Preview
Preview how a title, meta description and URL may look in Google results, cut by estimated pixel width the way Google truncates them.
Technical SEO · Open tool →