Free Website Tools
Nine free diagnostic tools for the things that quietly break websites: crawl rules, sitemaps, dead links, certificates, DNS, headers, and page weight. No signup and nothing stored. Run a one-off check here, then let NorthDuty watch the same signals continuously.
Available Tools
Pick a tool to run a free check — no signup required. More tools are added regularly.
Tool
SSL Checker
Free SSL certificate checker: expiry date, issuer, which hostnames it covers, TLS version and chain trust — plus the errors visitors hit and why.
Open SSL CheckerTool
DNS Lookup
Free DNS lookup tool: check A, AAAA, MX, NS, TXT (SPF/DMARC), CNAME and SOA records for any domain, with what each record breaks when it is wrong.
Open DNS LookupTool
HTTP Header Checker
Free HTTP header checker. Enter a URL to see its response headers and get a security-header grade based on HSTS, CSP, X-Frame-Options, and more.
Open HTTP Header CheckerTool
Meta Tag Checker
Free meta tag and Open Graph checker: see a page's title, description, canonical, robots and social preview tags, with the common mistakes flagged.
Open Meta Tag CheckerTool
Sitemap Validator
Free sitemap checker: validate an XML sitemap or sitemap index, count URLs, check lastmod dates, and catch the errors Search Console reports. No signup.
Open Sitemap ValidatorTool
robots.txt Tester
Free robots.txt checker and tester. Validate any site's robots.txt, see every rule and sitemap line, and test whether a URL is blocked for Googlebot.
Open robots.txt TesterTool
Response Time Checker
Free website response time checker. Enter a URL to see if the site is up, its HTTP status, and how fast it responds — with a fast, moderate, or slow rating.
Open Response Time CheckerTool
Broken Link Checker
Free online broken link checker. Scan a page for dead links, 404s, and server errors, see the exact status of each link, and learn how to fix them. No signup.
Open Broken Link CheckerTool
Page Size Checker
Free web page size checker. Enter a URL to see the HTML document size, whether it is compressed, and how many script, stylesheet, and image requests it makes.
Open Page Size CheckerOne-off checks, backed by continuous monitoring
These tools answer a single question right now — is this certificate about to expire, is this sitemap valid, are these headers set. They run in your browser against a small NorthDuty backend, with no signup and no data stored.
The catch with any one-off check is that it only describes this moment. Certificates expire, sitemaps drift, and headers get dropped in the next deploy. NorthDuty runs these same checks on a schedule and alerts you when something changes — so you find out before your customers do.
Start monitoring your website with NorthDuty today.
Run a free check above, then connect your site to NorthDuty to monitor user journeys, SSL, uptime, and page health continuously.
7 days with Pro features and limits, no credit card — then keep one daily journey on the free plan.