Domain Names / Bases
Extensions (TLDs)
How to Check Domain Availability
Enter your domain
Type a base name like mybrand or a full domain like mybrand.com. Press Enter or Space to add it.
Pick your TLDs
Add extensions to check: com, net, io, ai. The tool pre-fills .com .net .org by default.
Run the check
Click Check Domain Availability. Each domain+TLD pair is queried via RDAP in real time.
Bulk check
For long lists, upload a plain .txt file — one name per line. All names load as tags automatically.
Results are colour-coded: green = available, red = already registered, grey = unsupported TLD or network restriction.
Supported TLDs & What They Mean
The tool checks availability via each TLD's official RDAP server (Registration Data Access Protocol) — the same protocol domain registrars use internally. Supported extensions:
Bulk Domain Availability Checker
Checking one domain at a time is slow when you have a list of brand name ideas. This tool is a bulk domain availability checker: enter multiple base names and multiple TLDs at once, and it generates and checks every combination.
For example, entering base names nova, spark, orbit and TLDs com, io, ai produces 9 checks in one click: nova.com, nova.io, nova.ai, spark.com…
For very large lists, use the file upload: create a plain .txt file with one name per line, drop it into the upload zone, and all names load as tags automatically. The same works for TLDs.
Why use a bulk domain checker?
- Brainstorming brand names — quickly eliminate taken options across all extensions
- Domain investing — scan many names against multiple TLDs in one run
- Client research — present available alternatives when the ideal .com is taken
- Startup naming — compare .com vs .io vs .ai availability side by side
- Checking all extensions for a single brand to protect it from squatters
How Domain Availability Checking Works
Unlike many domain checkers that query a single registrar's API (which may include upsell suggestions or cached data), this tool queries each TLD's official RDAP endpoint directly from your browser.
RDAP (Registration Data Access Protocol) is the modern successor to WHOIS, standardised by IANA. Each registry (Verisign for .com/.net, ISOC for .org, etc.) operates a public RDAP server. A 404 Not Found response means the domain has no registration record — it's available. A 200 OK response means it's already registered.
Because requests go directly from your browser to the registry's server, results reflect the live registry state with no caching layer or middleman — the same data a domain registrar would see.
Limitations to be aware of
- CORS restrictions: Some RDAP servers block browser-originated requests. You will see a "Network error / CORS issue" result for those. Use
whoisor therdapCLI for those TLDs instead. - Unsupported TLDs: TLDs without a known RDAP endpoint return an "unsupported" message.
- Rate limits: A small delay between requests is added to avoid hitting RDAP server rate limits. Very large bulk lists may take a few minutes.
Frequently Asked Questions
How do I check if a domain name is available?
Type your domain idea into the tool above, select the TLD extensions you want to check, and click Check Domain Availability. Results appear within seconds via live RDAP queries.
Can I check domain availability across all extensions at once?
Yes. Add as many TLDs as you like to the Extensions field. The tool checks every base name against every TLD in one run — all 22 supported TLDs can be queued simultaneously.
Is this domain availability checker free?
Completely free. No account, no credit card, no rate limit on your side. The tool queries public RDAP servers directly with no intermediary.
Why do some results show an error instead of Available or Taken?
Two reasons: (1) the TLD is not yet in the supported list, or (2) the TLD's RDAP server blocks browser requests due to CORS policy. For accurate results on those TLDs, use a whois command from your terminal.
Which is better — .com, .io, or .ai for a tech startup?
.com is still the gold standard — highest user trust and broadest recognition. .io is widely understood in tech circles and name availability is better. .ai signals an AI-focused product, but securing the .com too is almost always worth it if it's available at a reasonable price.
How is this different from checking on GoDaddy or Namecheap?
Registrar websites query their own systems and may show "taken" for names they want to sell at a premium, or prompt upsells. This tool queries each registry's public RDAP server directly with no commercial interest — the result is purely technical availability data.
What does "domain availability" actually mean?
A domain is "available" when no registration record exists in the registry for that exact name + TLD combination. It does not mean the domain is free of trademarks — always check trademark databases before building a brand on a newly registered domain.