What is the difference between a gTLD and a ccTLD?

A gTLD is a generic top-level domain like com or org that is not tied to a country. A ccTLD is a two-letter country-code domain like uk or jp assigned to a specific territory under ISO 3166. Some ccTLDs are marketed globally regardless of origin.

What is a sponsored TLD?

A sponsored TLD, or sTLD, is run by a private organisation for a defined community and usually has registration restrictions. Examples include edu for US educational institutions and aero for the air-transport industry.

Are new gTLDs trustworthy?

New gTLDs such as app, dev, and shop are legitimate domains introduced by ICANN's expansion program. Some, like app and dev, even require HTTPS. Trust depends on the site, not the extension, but the TLDs themselves are valid.

Why do tech startups use .io and .ai?

These are technically country-code domains, io for the British Indian Ocean Territory and ai for Anguilla, but they are popular globally because the letters match input or output and artificial intelligence. They are sold openly to anyone.

Where does this data come from?

The reference follows the IANA root zone database, which is the authoritative list of delegated top-level domains, along with public notes about each TLD's sponsor and intended use.

What is the Top-Level Domain Reference?

Search top-level domains by name or type and see what each one is for, who sponsors it, and any registration restrictions. Covers gTLDs, country codes, sponsored TLDs, and new gTLDs. It runs free in your browser on Gera Tools, with nothing uploaded.

Top-Level Domain Reference

Name: Top-Level Domain Reference
Creator: Gera Tools
License: https://creativecommons.org/licenses/by/4.0/

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Understand any top-level domain

A top-level domain (TLD) is the final label of a domain name — the com in example.com. ICANN, through IANA, delegates every TLD in the root zone. They fall into a few families: generic TLDs (gTLDs), country-code TLDs (ccTLDs), sponsored TLDs (sTLDs) with registration restrictions, and the newer expansion gTLDs. This reference lets you search by name or filter by type to learn what each one is for.

The four TLD families

Generic TLDs (gTLDs) are the original open extensions not tied to any country. The best-known are com (commercial), org (organization), and net (network), all introduced in 1985. They can be registered by anyone anywhere in the world.

Country-code TLDs (ccTLDs) are two-letter codes derived from the ISO 3166-1 list of territories. Each territory’s government or appointed registry manages its own ccTLD and sets its own registration rules — some restrict to local residents, others sell to anyone globally.

Sponsored TLDs (sTLDs) are managed by a private organization for a specific community, with verified eligibility for registration. edu is available only to accredited US post-secondary institutions, gov only to US government entities, and mil only to the US military. aero serves the air transport industry, and museum serves accredited museums.

New gTLDs were introduced from 2013 onward as part of ICANN’s namespace expansion program, adding extensions like app, dev, shop, blog, health, and hundreds more. Some are open; others are restricted to an industry or company.

How it works

Each entry classifies a TLD and adds a note about its sponsoring organisation or intended use. The search matches your query against both the TLD string and the notes, and the type filter narrows the list to one family.

ccTLDs used as global brands

Some country-code domains are marketed worldwide because their letters happen to be meaningful in English or tech contexts:

TLD	Territory	Popular use
.io	British Indian Ocean Territory	Tech startups (input/output)
.ai	Anguilla	Artificial intelligence companies
.co	Colombia	Companies (alternative to .com)
.tv	Tuvalu	Media and streaming
.fm	Micronesia	Podcasts and radio
.me	Montenegro	Personal sites
.ly	Libya	URL shorteners (bit.ly)

Security signals from TLDs

A TLD can carry trust signals in both directions:

High trust: edu, gov, and mil require verified eligibility, so sites under them are what they claim to be.
HTTPS enforced: app and dev are on the HSTS preload list, meaning browsers require HTTPS before making any request — you cannot accidentally use them over HTTP.
No restriction: com, net, and most new gTLDs can be registered by anyone, so the TLD alone tells you nothing about the site’s legitimacy.

All filtering runs locally in your browser — no queries leave your device.