Looking up…
Where the facts come from.
- IANA's RDAP server for the root zone: the sponsoring organisation, the dates, the name servers and the DNSSEC record of the extension.
- ICANN's list of generic extensions: who operates each one, and whether it is a brand's own (Specification 13).
- IANA's RDAP bootstrap file: which registries answer RDAP.
- Contacts named in the records are often people; only organisations are shown.
Questions people ask.
What is a TLD?
The top-level domain, the last part of a domain name: .com, .si, .app. IANA's root zone list holds 1,437 of them in October 2026, 248 of which are two-letter country codes.
What is the difference between a country code and a generic extension?
Country codes (.si, .de, .io) follow ISO's two-letter codes and are run under each country's rules, some only for local people or companies. Generic extensions (.com, .app, .shop) are run under contracts with ICANN and sold through registrars worldwide.
What is a brand extension?
A generic extension a company runs for its own names only, such as .google. ICANN marks them under Specification 13 of their contracts; the public cannot register under them.
What do DNSSEC and RDAP mean here?
DNSSEC: the extension is signed, so names under it can be signed and their answers checked. RDAP: its registry answers the modern, structured replacement for WHOIS.
Who decides which extensions exist?
ICANN approves generic ones; country codes follow the ISO 3166 list. IANA keeps the root zone database that this page reads.
Hivex index
Short names, still free to register.
Starting something new? Hivex keeps a live index of short, brandable .si names nobody has claimed yet, each checked with the registry.
From code, or an AI assistant.
Hivex's free JSON API and MCP server check domains, DNS and registration records from your own code or from AI assistants that speak MCP. No key needed.
More Domain tools
- Domain availability checkerIs a name free? Live from the registry, on any extension.
- Brand name checkerOne name: 8 domain extensions and 10 platforms.
- Username checkerA username on 10 developer and social platforms.
- Domain name generatorIdeas from your words, each one checked free.
- Typosquatting checkerLookalikes of a domain: registered, taking mail, or free.
- Domain history checkerArchive captures by month, and signs of past owners.
- Is this domain for sale?Marketplace, parking and for-sale signs, and how to buy.
- Transfer date calculatorWhen a domain can move registrars, and what blocks it.
- Punycode converterUnicode to xn-- and back, with lookalike warnings.
- Bulk domain checkerUp to 200 names at once, live, with a CSV.
- WHOIS lookupRegistrar, dates, status locks and name servers, from the registry.
- Domain age checkerExact age from the registration date, plus the last change and transfer.
- Domain expiration checkerExpiry date, days left, and what happens if it lapses.
- Registrar lookupThe registrar, its IANA ID and abuse contact, and the transfer lock.
- Name strength checkerScore a name, and see where its misspellings lead.
- Domain hack generatorWords spelled across the dot, like fami.ly.
- Business name generatorNames for your business, each with a free .com.
- Short domain finder4 and 5 letter names you can still register.
- Dropped .si names.si names that just became free again.
- AI domain name generatorAI name ideas from a description, with a free .com.
- Domain value checkerWhat a name's value rests on, scored and explained.
- .si price comparisonWhat .si costs at each registrar, over the years.
- Domain prices by extensionFirst year, renewal and 5-year cost of any extension.
- Domain checkerIs a name free to register? Checked live on any extension.
Sources
- IANA: the root zone database
- ICANN: the gTLD list, with brand TLDs marked
- RFC 9224: Finding the authoritative RDAP service
- RFC 4033: DNS Security Introduction and Requirements
By Hivex. Updated 11 October 2026. Facts come from IANA's RDAP for the root zone and ICANN's gTLD list, kept up to a day; nothing you type is stored.