Check a domain name across major TLDs against authoritative RDAP servers — a missing record means likely available. TLDs without RDAP fall back to a DNS heuristic. Always confirm with a registrar before purchasing. Uses cloud-based processing.
Content reviewed October 2026 · About Toolzum
Look up domain registration information using public RDAP APIs. Check registrar, expiration date, name servers, and more.
Discover subdomains via public certificate records plus live DNS checks of common names. Read-only lookups run from your browser — the domain you check is visible to crt.sh and Google DNS, as with any lookup.
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Major TLDs including .com, .net, .org, .io, .dev, .co, .app, and more. The checker queries DNS records to determine if a domain is registered or available.
RDAP answers are authoritative: a record means registered, a missing record means likely available (premium/reserved names can still surprise you). Where a TLD has no RDAP, the tool falls back to DNS queries — weaker signal. Always verify with a registrar before purchasing.
Yes. Enter a base name and the tool checks it across all supported TLDs simultaneously, showing availability status for each extension in a single table.
Yes — after a check, one click tests 6 variants (get-, -hq, -app, try-, -ly, the-) on .com through the same RDAP-first pipeline. Listed alternatives are checked verdicts, not guesses.
We store no search history. But the checks themselves are DNS-over-HTTPS queries to Google's public DNS resolver, so queried names are visible to that third party — same as any DNS lookup.
All 10 in one run: .com, .net, .org, .io, .dev, .app, .co, .me, .tools, .xyz — RDAP first per name, falling back to DNS A plus MX lookups (a mail-only domain still counts as registered). Each lookup is capped at 10 seconds.
WHOIS Lookup
Look up domain registration information using public RDAP APIs. Check registrar, expiration date, name servers, and more.
Subdomain Finder
Discover subdomains via public certificate records plus live DNS checks of common names. Read-only lookups run from your browser — the domain you check is visible to crt.sh and Google DNS, as with any lookup.