All tools
Query any DNS record live: A, AAAA, MX, TXT, DS, DNSKEY and more.
Has your DNS update propagated? Compare answers across 5 public resolvers.
Check via RDAP whether a domain is still available.
Check MX, reverse DNS and port availability of your mail servers.
Build a valid SPF record with lookup counter and RFC warnings.
DMARC policy from p=none to p=reject, every option explained.
Define which certificate authorities may issue for your domain.
Generate the TXT record and policy file for enforced TLS delivery.
Inspect the DKIM key for a domain and selector, including key length.
The DS and DNSKEY chain made visible: signed, valid or broken?
Decode email headers: delivery path, SPF/DKIM/DMARC results. Runs entirely in your browser.
Convert internationalized domains to punycode and back.
All checks as a JSON API plus an embeddable score badge.