What Is a TLD? An Introductory Guide to Top-Level Domains

By Judit Ruiz Ricart

One of the most crucial challenges of building a successful online presence is choosing the perfect domain name. A close second in terms of difficulty comes shortly after, as you’re presented with a long list of choices to pair with your idea. These short strings of text are known as top-level domains (or TLD), and play a more significant role that you may think.

Your site’s TLD is meant to serve as a summary of your site’s main characteristics, and can have a huge impact on the way visitors perceive your brand. With this in mind, you should get familiar with the concept of top-level domain and understand the different types of TLDs in order to identify the best match for your website.

What is a TLD?

A top-level domain (TLD) is the rightmost segment of a domain name, located after the last dot. Also known as domain extensions, TLDs serve to recognize certain elements of a website, such as its purpose, owner or geographical area. For example, a .edu top-level domain allows users to immediately identify that site as a higher educational institution.

The concept of TLDs was created by ARPANET in the 1960s with the goal of easing the process of memorizing IP addresses. It wasn’t until the early 1980s that the earliest top-level domains were developed and the structured categorization you’ll come across when registering a domain name today was introduced. Each top-level domain has an independent registry managed by a designated organization under the guidance of the Internet Corporation for Assigned Names and Numbers (ICANN).

Different types of top-level domains

The ICANN classifies top-level domains into different categories depending on the site’s purpose, owner and geographic location.

There are 5 official types of TLDs:

01. Generic Top-Level Domains (gTLD)

Generic top-level domains, commonly known as gTLD, are the most popular and familiar types of domain extensions. They contain three or more characters, and are open for registration by anyone. The origin of their categorization title dates back to the 1980s, when TLDs were simply differentiated between those related to the geographical location of a site and those that weren’t - hence, generic.

Over time, the use of certain generic top-level domains became more strictly controlled to ensure they met certain standards, leading to the creation of a new category known as sponsored top-level domains. Of the initial seven available gTLDs only three can still be registered without restriction: .org, .com. and .net.

The most common usages of generic top-level domains include:

.com - for commercial sites
.org - for organizations
.net - for networks
.info - for information platforms
.biz - for businesses

In mid-2011, ICANN approved a change to the domain name system that expanded the original gTLDs from 22 to over 1,200. These innovative options, aptly named New gTLDs, saw the incorporation of official domain extensions such as .berlin, .contact and .wow. You can see the complete top-level domain list on IANA’s database (Internet Assigned Numbers Authority, a subdivision of ICANN).

02. Sponsored Top-Level Domains (sTLD)

As the name suggests, sponsored top-level domains are those proposed and supervised by private organizations. These entities can be businesses, government agencies or other types of organized groups, and they have the final word on whether an applicant is eligible to use a specific top-level domain based on predefined community theme concepts.

Unlike with gTLDs, the sponsored top-level domain list only includes a small, limited number of options. Some date back to the original 1980s domain extensions (including .edu, .gov and .mil), whereas others have been created in recent years.

Among them, some of the most popular sTLDs are:

.edu - for higher educational institutions
.gov - for United States governmental agencies
.cat - for Catalan linguistic and cultural community
.museum - for museum organizations
.travel - for travel industry businesses

03. ccTLD – Country Code Top-Level Domains (ccTLD)

There are 312 country code top-level domains established for specific countries and territories, identifying them with a two-letter string. These domain extensions have dedicated managers who ensure each ccTLD is operated according to local policies and meets the cultural, linguistic and legal standards of the region.

Besides local businesses and individuals, ccTLDs are widely used by large corporations with regional sites that operate independently. In these cases, domain extensions serve the same purpose as a subdomain. If you plan on using a country code top-level domain on your site, make sure to take this into account when searching for the best domain registrar as not all platforms offer ccTLD registration.

In 2012, the ICANN announced the addition of the first ccTLDs using non-latin characters to the domain name system root zone. These domain extensions, known as internationalized country code top-level domains (IDN ccTLD) include languages such as Arabic, Chinese, Hebrew and Cyrillic.

Some of the most well-known ccTLD include:

.us - for the United States
.es - for Spain
.fr - for France
.it - for Italy
.br - for Brazil

04. Infrastructure Top-Level Domain (ARPA)

This special category contains only one TLD: the Address and Routing Parameter Area (ARPA). The .arpa domain extension is managed directly by the IANA for the Internet Engineering Task Force (IETF) under the guidance of the Internet Architecture Board (IAB) and is only used for technical infrastructure purposes.

05. Test top-level domains (tTLD)

Test top-level domains are reserved for documentation purposes and local testing, and cannot be installed into the root zone of the domain name system. According to the IETF, the reason for reserving these specific domain extensions is to reduce the possibility of conflict and confusion.

There are four tTLDs:

.example - for place holding
.invalid - for invalid domain names
.localhost - for usage in local networks
.test - for testing purposes

What is the purpose of the different TLDs?

Early on, top-level domains were limited and had a very specific purpose. Over time, however, the top-level domain list has surpassed three digits and most restrictions have long been abandoned in favor of creativity and branding.

While you’ll still need to meet certain principles if you are planning to register your site with a sTLD or ccTLD, choosing a gTLD will most likely come down to the domain name cost and your personal preference. See how the different options pair with your brand name and whether there are any that can particularly strengthen your message.

You should also take into account how easy a TLD is to pronounce and remember when it’s combined with your domain name. While top-level domains have no direct impact on your site’s SEO performance, unusual or complex domain extensions can lead to fewer inbound links and direct traffic.