Free website diagnostic tools
Check DNS records, SSL certificates, email authentication, and more.
DNS lookup
Query A, AAAA, CNAME, NS, TXT, SOA, and MX records for any domain.
MX lookup
Find mail exchange servers, their priorities, and verify they resolve correctly.
SSL checker
Inspect SSL/TLS certificates, expiry dates, cipher suites, and protocol support.
DMARC checker
Validate DMARC, SPF, and DKIM records to ensure your email authentication is correct.
Blacklist check
Check if an IP address is listed on any of 45+ email blacklists (DNSBLs).
SMTP diagnostics
Test an email server's SMTP connection, TLS support, reverse DNS, and open relay status.
What's my IP
Instantly see your public IP address with geolocation and network details.
IP lookup
Get geolocation, ISP, organization, and network information for any IP address.
Email header analyzer
Parse raw email headers to trace the delivery path and identify delays or issues.
HTTP header checker
Inspect all HTTP response headers returned by any website, including caching and security headers.
Website speed test
Measure DNS resolution, TLS handshake, TTFB, and total load time with a timing waterfall.
DNSSEC checker
Validate DNSSEC signing, DNSKEY and DS records, and verify the chain of trust for any domain.