First CH Apps / Bulk Domain Availability Check
Enter a single name and our server queries RDAP — the HTTPS API that replaces WHOIS — plus public DNS for ten major TLDs, and lists which are taken and which look free. Useful when you are naming a product or a company.
Every verdict is one of three: registered, possibly unregistered, or inconclusive. We never claim a name is definitely free: registry-reserved words, premium pricing and registry-specific policies can all block a registration that RDAP has no record of. Confirm availability and price at a registrar (this page carries no affiliate links to any of them).
e.g. firstch — pasting a full domain such as example.com works too, we strip the TLD. Internationalised (non-ASCII) names are not supported.
Registries hold back names that RDAP has no record of: registry-reserved terms, country names, one- and two-character labels, and premium-priced names. Some registries also take minutes or hours to publish a brand-new registration over RDAP. This page is good for narrowing a shortlist, but check the actual availability and price at a registrar before you commit.
RDAP is mandated for gTLDs (.com, .net, .org, .dev, .app, .ai and so on); country-code TLDs are not covered. Where IANA's bootstrap lists no RDAP server — .jp, .co.jp, .io and .co here — we infer purely from whether public DNS shows a delegation, because we never guess a server URL. A registered domain whose owner never set name servers answers NXDOMAIN and will therefore read as “possibly free”. Use the JPRS WHOIS search for authoritative .jp data. Note also that .co.jp is restricted to companies registered in Japan, one domain per company.
A free domain is not the same as a name you are allowed to trade under. Using a name identical or similar to someone else's registered mark within their goods and services can get you an injunction, and the domain itself can be transferred away under the UDRP. Search the relevant national trade mark database (J-PlatPat in Japan, TMview in the EU, TESS in the US) for at least your own industry class before you decide.
Search rankings do not change with the TLD, but trust and typability do. For a Japan-facing business .jp or .co.jp reads as local; .com, .dev and .io travel well internationally; .ai has become the default for AI products. Note that .dev and .app are HSTS-preloaded, meaning browsers refuse plain HTTP — good for security, impossible on legacy hosting that cannot serve HTTPS.
If the .com is gone, adding a hyphen or pluralising is usually a mistake: such names are hard to say out loud and easy to mistype. Taking a different TLD, or shortening the name into a coined word, is easier to live with. If you want to buy an existing domain, work through a registrar's broker service — you cannot judge on your own whether the seller's asking price is reasonable.
Sent: only the name extracted from your input (as ten domain names, one per TLD). Our server (Cloudflare Workers) makes HTTPS GET requests to the IANA bootstrap (data.iana.org) and to each registry's RDAP server, plus NS queries to Cloudflare's public DNS (1.1.1.1). A single check is capped at 44 outbound lookups.
Stored: nothing. The check lives entirely inside one request and writes neither the name nor the result to any database (no KV, no D1). It leaves memory when the request ends.
Returned: the three-way verdict per TLD, the evidence behind it (what RDAP answered, whether DNS shows a delegation) and — for registered domains — the public registrar name, creation date and expiry date. The raw RDAP response is never relayed.
Not read: registrant, administrative and technical entities (names, addresses, phone numbers, email). Because we do not handle personal data, we read no further than the registrar, which is a company.
Note: the only servers we query are the registry servers named by the IANA bootstrap and a fixed public DNS resolver — there is no way to point this app at an arbitrary URL. The name is normalised to a single label (letters, digits and hyphens, 63 characters max) before use.
Neutrality: this page carries no affiliate links to any registrar or reseller. Nothing in the verdict is influenced by a sale.
POST /domain-availability/api/check with JSON ({"name": "firstch"}) or a form body and you get the same result as JSON (no auth, nothing stored).