A top-level domain (or Top-Level Domain, often referred to by the acronym TLD) represents the last segment of an Internet domain, i.e. the string of characters placed after the rightmost point of the URL. Because of its position, the TLD can also be called a domain extension.
In a domain name such as youngplatform.com, for example, the TLD corresponds to “.com“.
The main function of TLDs is to classify and categorise the domain, communicating the essential details of the website to the user. Thanks to TLDs, it is possible to obtain information on the owner, the geographical area or the primary purpose of the domain.
TLDs also allow the Domain Name System (DNS), the system that translates IP addresses into names that can be easily understood and memorised by humans, to address and locate websites, allowing the browser to display the correct content.
Although in the early history of the Internet it was only possible to choose between 6 domain extensions, today users have a wide variety of top-level domains at their disposal. The spread of blockchain technologies has also led to the emergence of NFT domains, a suite of smart contracts that grant full control to the domain owner.
The IANA (Internet Assigned Authority) in 2015 updated and distinguished the available TLD categories.
Among the main types of domain extensions, we can identify:
- Generic Top-Level Domain (gTLD): they describe the main activities associated with an Internet domain. Within this classification, it is possible to identify some of the most widely used TLDs such as “.com“, referring to commercial activities, “.org” for organisations or associations or even “.net“, initially used by Internet providers.
- Country-Code Top-Level Domain (ccTLD): category specifying the geographical origin of an Internet domain. The “.it” TLD, for example, is used to represent dependence on Italy, while “.fr” refers to France.
Country-code Top-Level Domains are also exploited by Google to geolocalise the website if the latter has different versions based on the language and nationality for which it is intended.
- Sponsored Top-Level Domain (sTLD): top-level domains sponsored by a community or private organisation. These include “.edu“, mainly exploited by universities or academic bodies, or even “.xxx“, used by sites specialising in pornographic content.
The complete and up-to-date list of all TLDs can be consulted on the IANA website.