domain.check

Find your domain.

Check domain availability across 741 extensions in seconds. DNS-first checks with RDAP and WHOIS only when needed. Free, no sign-up.

Extensions

741 supported

Filter by category
  • .com
  • .de
  • .net
  • .org
  • .io
  • .ai
  • .app
  • .dev
  • .co
  • .me
  • .xyz
  • .online
  • .site
  • .store
  • .shop
  • .tech
  • .cloud
  • .blog
  • .info
  • .pro
  • .uk
  • .fr
  • .eu
  • .us
  • .ac.uk
  • .asn.au
  • .co.id
  • .co.il
  • .co.in
  • .co.jp
  • .co.kr
  • .co.nz
  • .co.th
  • .co.uk
  • .co.za
  • .com.ar
  • .com.au
  • .com.bd
  • .com.br
  • .com.cn
  • .com.co
  • .com.eg
  • .com.hk
  • .com.mx
  • .com.my
  • .com.ng
  • .com.pe
  • .com.ph
  • .com.pk
  • .com.pl
  • .com.sa
  • .com.sg
  • .com.tr
  • .com.tw
  • .com.ua
  • .com.vn
  • .edu.au
  • .gen.nz
  • .gov.au
  • .gov.uk
  • .govt.nz
  • .id.au
  • .ltd.uk
  • .me.uk
  • .net.au
  • .net.br
  • .net.cn
  • .net.co
  • .net.in
  • .net.nz
  • .net.sg
  • .net.za
  • .org.au
  • .org.br
  • .org.cn
  • .org.il
  • .org.in
  • .org.nz
  • .org.sg
  • .org.uk
  • .org.za
  • .plc.uk
  • .bot
  • .chat
  • .codes
  • .computer
  • .digital
  • .email
  • .engineer
  • .engineering
  • .forum
  • .host
  • .link
  • .network
  • .page
  • .run
  • .science
  • .sh
  • .software
  • .systems
  • .technology
  • .tools
  • .website
  • .wiki
  • .zone
  • .academy
  • .agency
  • .associates
  • .attorney
  • .biz
  • .business
  • .capital
  • .careers
  • .charity
  • .coach
  • .college
  • .company
  • .construction
  • .consulting
  • .contractors

How domain availability checks work

domain.check runs a waterfall instead of querying a WHOIS server for every name. The first stage asks DNS for A, AAAA and NS records. Any answer proves the domain is registered and ends the check in milliseconds, because DNS is cached worldwide and speaks UDP.

When DNS returns nothing, the second stage asks the registry directly through RDAP. A 404 from the registry means the name is available; a record supplies registrar, dates, status and nameservers as structured JSON. Registries that do not publish RDAP are queried through WHOIS, whose text is matched against conservative availability markers.

Every result is cached for a short time and identical checks are coalesced, so repeated searches and a full run across all 741 extensions stay fast without hammering registries. Favorited TLDs are checked first and can be pinned at the top of the results.

Frequently asked questions

How does domain.check check availability?

It checks DNS first. If the domain has A, AAAA or NS records, it is registered. If DNS returns nothing, domain.check asks the registry through RDAP and falls back to WHOIS for country-code TLDs without RDAP support.

What is the difference between DNS, WHOIS and RDAP?

DNS is a fast, globally cached lookup that proves a domain is delegated. RDAP is the modern HTTP and JSON successor to WHOIS and returns structured registry data. WHOIS still covers ccTLDs that do not publish RDAP.

Are the results accurate?

A DNS record is definitive proof of a registration. For domains without DNS records, the answer comes directly from the registry. Very recent registrations, registry downtime or rate limits can still cause temporary errors, which are shown instead of a guess.

Why do some extensions show an error?

Some registries block automated queries, rate-limit requests or publish neither WHOIS nor RDAP data. Rather than claiming the domain is free, domain.check marks the check as failed so you can retry later.

Is domain.check free?

Yes. The tool is free, needs no account and stores favorites only in your browser. There is no tracking.

Which TLDs are supported?

741 extensions: every country-code TLD, popular multi-part suffixes such as co.uk, and the most-used generic TLDs with at least 3,000 registrations. Closed brand TLDs and IDN extensions are excluded.