As of a recent comprehensive count, there are 1589 Top-Level Domains (TLDs) tracked within the IANA root database. This figure encompasses all TLDs, including those actively published in the domain name system's root zone file, as well as those that are no longer active but are still recorded for historical or administrative purposes.
Understanding Top-Level Domains (TLDs)
A Top-Level Domain (TLD) is the final segment of a domain name, found after the last dot. For example, in "example.com," ".com" is the TLD. TLDs are essential for the internet's addressing system, providing structure and categorization to websites and email addresses. They are managed by the Internet Assigned Numbers Authority (IANA), which operates under the oversight of the Internet Corporation for Assigned Names and Numbers (ICANN), the global non-profit organization responsible for coordinating the maintenance and procedures of several databases related to the namespaces and numerical spaces of the Internet.
The Breakdown of TLDs
While the IANA root database lists 1589 TLDs, it's important to understand the different categories that contribute to this total. Not all listed TLDs are actively used or present in the current root zone file, which is the authoritative list of all actively delegated TLDs.
A recent analysis of the IANA root database reveals the following composition:
| Category | Number of TLDs | Status | Included in Root Zone File? |
|---|---|---|---|
| Total TLDs in IANA Database | 1589 | Comprehensive count of all TLDs ever registered or tracked. | Varies |
| Actively Assigned/Used TLDs | 1502 | TLDs that are currently active and delegated, forming the operational core of the DNS. | Yes |
| Not Assigned (Revoked) TLDs | 68 | TLDs that were once delegated but are no longer in use, often due to policy changes or non-compliance. | No |
| Retired TLDs | 8 | TLDs that have been formally removed from active use and are no longer available for delegation. | No |
| Test Domains | 11 | TLDs reserved for testing and evaluation purposes by ICANN and IANA, not for public registration. | No |
Note: The 1502 actively assigned/used TLDs are derived by subtracting the revoked, retired, and test domains from the total number tracked in the IANA database (1589 - 68 - 8 - 11 = 1502). The root zone file, which facilitates global domain resolution, primarily includes these actively assigned TLDs.
Types of Top-Level Domains
TLDs are broadly categorized to reflect their purpose, geographical association, or the community they serve. The primary categories include:
- Generic Top-Level Domains (gTLDs): These are perhaps the most common and recognizable TLDs. They often suggest the general purpose or type of organization using the domain.
- Original gTLDs: Such as
.com(commercial),.org(organizations),.net(network),.edu(educational),.gov(government),.mil(military), and.int(international treaty organizations). - New gTLDs: Introduced to significantly expand the domain name space, these include a vast array of options from
.appto.xyz,.shop,.blog, and even brand-specific TLDs like.google.
- Original gTLDs: Such as
- Country Code Top-Level Domains (ccTLDs): These two-letter TLDs are associated with specific countries or sovereign states, adhering to the ISO 3166-1 alpha-2 standard.
- Examples:
.us(United States),.uk(United Kingdom),.de(Germany),.jp(Japan),.cn(China).
- Examples:
- Sponsored Top-Level Domains (sTLDs): These are specialized TLDs that have a sponsor representing a specific community or niche. The sponsor enforces rules and eligibility requirements for registrants.
- Examples:
.aero(air-transport industry),.coop(cooperatives),.museum(museums),.jobs(human resources community),.travel(travel industry).
- Examples:
- Infrastructure TLD (.arpa): This is a single, special TLD,
.arpa, which is reserved exclusively for technical infrastructure purposes, primarily for reverse DNS lookups.
The Dynamic Nature of TLDs
IANA, under ICANN's guidance, continuously manages the TLD landscape. This involves:
- Delegating new TLDs: Periodically, new gTLDs are approved and launched, providing more options for domain registration.
- Maintaining existing TLDs: Ensuring the stable operation and adherence to policies for all active TLDs.
- Retiring or revoking TLDs: Domains that no longer meet policy requirements or are deemed obsolete may be removed from active delegation.
This ongoing management ensures the internet's naming system remains organized, functional, and adaptable to global needs.
