Free website tools.
Quick checks for the things that go wrong behind a website: DNS, certificates, redirects, headers, email and search settings. No sign-up, no downloads.
Look inside a website
DNS lookup
See the A, AAAA, CNAME, MX, NS, TXT, SOA and CAA records for any domain.
Open the tool →📋HTTP header checker
View the response headers a website sends, after following redirects.
Open the tool →🔒SSL certificate checker
Check a certificate’s issuer, expiry date, protocol and chain.
Open the tool →↪Redirect checker
Trace every redirect hop, with status codes and timings.
Open the tool →📅WHOIS and domain expiry
Find a domain’s registrar, creation date and expiry date.
Open the tool →✉MX record lookup
Check a domain’s mail servers, SPF and DMARC records.
Open the tool →🤖Robots.txt checker
Read and check a site’s robots.txt rules and sitemap lines.
Open the tool →🛡Security headers checker
Grade a site’s browser security headers from A to F.
Open the tool →Is it working?
Is it down?
Check any website from our server and twelve places around the world.
Open the checker →⚡Website speed test
See how fast a page loads and where the time goes.
Test a site →🔔Monitor and alerts
Watch your sites and get an email when one goes down.
Open Monitor →Each tool tests public websites only, from our servers, and we limit how often one visitor can run them. Results are a snapshot of the moment you ask. How our checks work.