Free Website Tools
Quick, free diagnostics for the website signals that matter. Run a one-off check here, then let NorthDuty watch the same signals continuously and alert you when they change.
Available Tools
Pick a tool to run a free check — no signup required. More tools are added regularly.
Tool
SSL Checker
Free SSL/TLS certificate checker for expiry date, issuer, validity, TLS protocol, and chain trust. No signup required.
Open SSL CheckerTool
DNS Lookup
Free DNS lookup tool. Enter a domain to see its A, AAAA, MX, NS, TXT, CNAME, and SOA records — no signup required.
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. Enter a URL to see its title, meta description, canonical, robots, and Open Graph / Twitter Card tags, with common issues flagged.
Open Meta Tag CheckerTool
Sitemap Validator
Free XML sitemap validator. Enter a sitemap URL to check that it is valid, see how many URLs it contains, whether entries carry lastmod, and any structural problems.
Open Sitemap ValidatorTool
robots.txt Tester
Free robots.txt tester to parse rules, list sitemap directives, and test whether a URL path is allowed for a user-agent.
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 broken link checker. Enter a URL and NorthDuty scans its links and reports which ones are broken (404s, errors, or unreachable) — no signup required.
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 SSL, uptime, page health, visual changes, and user journeys continuously.
Free forever plan, no credit card required — add your base URL and monitoring starts in minutes.