DNS

What it does: looks up the records behind a domain name — the "phone book" of the internet. DNS is what turns a name like example.com into the address and mail/verification info computers actually use. It queries over DNS-over-HTTPS, so it works even on networks that block normal DNS.

What you need: a domain name (e.g. example.com). Pick a record type or look up the common ones.

Safe to run: yes — a read-only lookup.

What to expect / reading results: each record type answers a different question — A = the IPv4 address, AAAA = the IPv6 address, MX = which mail server handles the domain, TXT = things like SPF/domain-verification. "NXDOMAIN" means the name doesn't exist (a typo, or it was never registered); an empty result for one type just means the domain has no record of that type.