Queries live registry data over RDAP straight from your browser — no backend, no API key, no rate-limited third-party service. A 404 from the registry means nobody owns it yet.
RDAP endpoints are queried directly per TLD (Verisign for .com/.net, NIC.US for .us, Identity Digital for .ai, .io registry, etc.), falling back to the rdap.org bootstrap redirector when a direct endpoint isn't hardcoded. Known limitation: rdap.org returns 404 both when a domain is unregistered and when it simply has no bootstrap entry for that TLD — for less common ccTLDs this can misreport an owned domain as "available." If a result surprises you (e.g. a domain you already own shows available), treat it as unverified and check the registry directly rather than trusting it. .lt is a ccTLD run by Kaunas University of Technology (registry: domreg.lt); RDAP coverage for it is inconsistent, so if it shows "unknown" here, check directly at domreg.lt — they have their own availability checker. Always confirm with a registrar (Namecheap, Porkbun, Cloudflare, or any accredited registrar for the TLD) before you rely on this to buy. This does not check aftermarket/premium listings.