Domain Name Availability

Check if a domain is registered using RDAP WHOIS. Free, no API key, pure client-side.

Checks RDAP databases for domain registration status. Note: "Not found" doesn't guarantee true availability — always verify with a registrar before purchasing.
  • This checks RDAP, NOT a registrar. RDAP can confirm if a domain is registered, but cannot check if it's available for purchase
  • A "not found" result means the domain is NOT registered — but you still need to buy it through a registrar
  • Some TLDs (like .io, .ai) have limited RDAP support and may not return accurate results
  • For purchase, always verify availability with a registrar like Namecheap, Cloudflare, or GoDaddy
  • RDAP is rate-limited (~200 queries/hour per IP). Don't automate bulk checks.

About this Domain Availability Checker

Domain availability checks query registration data to see whether a name appears registered. “Available” signals from RDAP/WHOIS are strong hints but final registration always happens at a registrar checkout.

Client-side RDAP checks avoid giving a middleman your brand-name brainstorms when possible.

How to use this tool

  1. Enter the domain you are considering.
  2. Run the check and read registered vs not-found style results.
  3. Confirm at your registrar before branding decisions.

Common use cases

FAQ

Can results be wrong?

Propagation, thin registries, and rate limits can cause edge cases—verify at purchase time.

Privacy

DevToolBox tools are designed to process data in your browser whenever possible. Read our Privacy Policy and About page for details on client-side processing and network lookups.

Related tools

WHOIS Lookup · ARIN Lookup

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