Free Developer Tools

Test if a website supports IPv6. One live DNS lookup checks a domain's AAAA records, name servers, and mail servers, and scores each layer so you can see where IPv6 coverage stops.

Generate DMARC records to help secure your domain with our free tool. Quickly set up DMARC policies and defend your domain against spoofing or phishing attacks.

Check your domain's MX records and mail server configuration instantly. Get mail exchange servers, priority values, IP addresses, ASN, plus A, AAAA, and CNAME records for complete email and domain infrastructure visibility.

Validate your domain's SPF record with our free SPF Checker tool.

Generate properly formatted CAA DNS records for any domain in five formats - Generic CAA, BIND zone, Legacy TYPE257, tinydns, and dnsmasq. Pick from 60+ certificate authorities, control wildcard and non-wildcard issuance, add an iodef contact, or pull a domain's current policy as a starting point.

Check CAA DNS records for any domain and quickly verify certificate authority permissions with our online CAA record checker tool.

Check your domain's DMARC record in seconds with our free lookup tool.

Instantly retrieve and verify DNSKEY records for any domain. Confirm DNSSEC is enabled, inspect published key data, identify KSK and ZSK types, and troubleshoot missing or misconfigured DNSSEC keys.

Use Our tool to Check if your domain has DNSSEC (DNS Security Extensions) enabled. Ensure your domain is protected against DNS spoofing and cache poisoning attacks by validating the presence of DNSSEC signatures.

Enter any name server to see which domains delegate their DNS to it. Run a reverse NS lookup with exact or wildcard matching, plus TTL and last-seen dates.

Resolve any IP address to its hostname with a free reverse DNS (PTR) lookup. Enter an IPv4 or IPv6 address and get the canonical hostname in seconds.