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.

Top-Level Domain Reference

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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.

How it works

Each entry classifies a TLD and adds a note about its sponsoring organisation or intended use. gTLDs like com, org, and net are open and not tied to a country. ccTLDs are two-letter codes assigned to territories under ISO 3166, such as uk, de, and jp. sTLDs like edu, gov, and aero serve a defined community and restrict who may register. New gTLDs such as app, dev, and shop came from ICANN’s namespace expansion. The search matches your query against both the TLD string and the notes.

Tips and notes

Some ccTLDs are repurposed far beyond their home country: io (British Indian Ocean Territory), ai (Anguilla), co (Colombia), and tv (Tuvalu) are all sold globally because their letters are memorable. The app and dev gTLDs are on the HSTS preload list, so browsers require HTTPS for any site under them. Restricted TLDs like edu and gov cannot be registered freely, which makes them strong trust signals. All filtering runs locally in your browser.