What are the different types of domains?

If you’re looking to run a website or online shop, you’ll un­doubtedly be faced with the challenge of finding a suitable web address. With the many different domain types out there, though, finding the right domain is often not as simple as it looks. For one, you’ll need to decide on a strong and unique name, whereby the second-level and third-level domain types play an important role. On the other hand, you’ll need a suitable domain ending, also known as a top-level domain.

The following guide will clear up the most important questions on domain types. What types of domain endings exist and what do they mean? How do the different domain levels within a domain name dif­fer­en­ti­ate from one another? And how can you find out which type of domain is best suited to your project?

The Internet connects technical devices and services across the whole world. This is made possible among other things by the protocol stack TCP/IP and the domain name system (DNS). TCP/IP makes sure that every computer and every mobile device as well as every web service that is available via the Internet has a clearly defined IP address such as 93.184.216.34. The DNS trans­lates these addresses using name servers into human-readable domains like www.example.org. This process is also called name res­ol­u­tion.

When you want to access websites and online shop via a browser’s address bar such as Firefox or Google Chrome, or you want to connect to a server or another device on the Internet, you end up con­tact­ing these in­di­vidu­al domain addresses.

Top-level domains, or TLDs for short, represent the highest level of name res­ol­u­tion in the domain name system hierarchy. As a domain component of the highest level, a top-level domain always appears as the last part of a web address (to the right of the last dot), which is why TLDs are also referred to as domain endings. In the domain example already used, www.example.org, the top-level domain is the address part org.

The al­loc­a­tion of TLDs is managed by IANA, a division of ICANN (Internet Cor­por­a­tion for Assigned Names and Numbers), an or­gan­isa­tion founded in 1998. IANA de­term­ines which domain endings exist and sells the rights to assign them to re­gis­trars, who in turn negotiate with domain providers on the sale of the now more than 1,000 domain endings.

When web addresses were first launched, there were initially only the following seven top-level domains:

ccTLDs are a special category of domain ex­ten­sions ad­min­istered by the re­spect­ive country. ccTLDs always consist of two letters, e.g., the codes de for Germany or us for the United States. In addition to country code TLDs, ICANN has also assigned ccTLDs for dependent ter­rit­or­ies that are geo­graph­ic­ally separated from the parent country. For example, parallel to the Aus­trali­an domain .au, there are also ccTLDs for the Cocos Islands (cc), the Christmas Islands (cx), Norfolk Island (nf) or Heard and McDonald Islands (hm), all of which are Aus­trali­an outlying ter­rit­or­ies.

The guidelines that apply to re­gis­ter­ing a country-specific domain are up to each country. Many smaller and poorer countries have taken advantage of this fact and marketed their ccTLD spe­cific­ally. For example, the dwarf state of Tuvalu sold its domain to the company DotTV for around 35 million pounds and invested the money in IT in­fra­struc­ture. Tuvalu was also able to pay the fee for its admission as the 189th member of the United Nations on the 5^th of September 2000, from the ‘.tv-deal’. More in­form­a­tion and key facts can be found in our detailed article on the topic of ccTLDs.

The following table presents some country-specific TLD examples:

The domain type of the so-called generic top-level domains differs from country-specific addresses in that it does not cover a geo­graph­ic­al area, but a thematic area. In addition, generic addresses are divided into two types:

Non-sponsored gTLDs are subject to cent­ral­ised control and man­age­ment by ICANN, which co­oper­ates with various partners for this purpose. Ori­gin­ally, these endings were to be assigned only under certain con­di­tions: For example, the domain .net was meant to be reserved ex­clus­ively for Internet service providers. Today, like many other non-sponsored gTLDs, it is also available for other companies and or­gan­isa­tions as well as for private in­di­vidu­als.

Sponsored gTLDs, on the other hand, are subject to the re­stric­tions de­term­ined by the re­spect­ive sponsor. In this case, the re­spect­ive in­de­pend­ent companies or or­gan­isa­tions are also re­spons­ible for the ad­min­is­tra­tion and control of the gTLDs. A sponsored domain example is .gov, which to date has been ad­min­istered by the US au­thor­it­ies as sponsor and is used for American gov­ern­ment websites or services.

The new top-level domains released at regular intervals since 2013 like .blog, .web or .beauty count towards generic top-level domains.

A second-level domain is the freely se­lect­able name below any top-level domain. For this reason, this component of a web address is also called the domain name. Although it is located below the TLD in the domain hierarchy, the second-level domain is by no means less relevant than the ending. The real situation tends to be the other way around: the domain name is much more important than the extension from both a user and SEO per­spect­ive, as it can better describe the content of a site and even contain keywords.

In our domain example www.example.org the second-level domain is 'example'.

There are even some country-specific, second-level domains, as displayed in the below table of com­bin­a­tion examples with the TLD .uk:

Op­tion­ally, another domain level can be sub­or­din­ated to the domain name. This type of domain is placed before the second-level domain and is called a third-level domain or sub-domain. The function of such a third-level domain is to structure the contents of a website or web shop in a mean­ing­ful way. Different topics or different language versions of a project can be clearly marked in the web address, while the domain name remains unchanged.

In the domain example www.example.org, the well-known sub-domain www is used. Par­tic­u­larly in the early days of the Internet and the world wide web, this signalled to users that they were dealing with a web ap­plic­a­tion, for example a website with in­form­a­tion. Today, however, since it’s no longer necessary to enter the third-level domain in order to visit a website, it’s becoming in­creas­ingly rare to come across operators who advertise their website including the ‘standard’ third-level domain, www. More common sub-domains that you encounter much more often nowadays look like the following – staying with the domain example example.org:

• en.example.org
• es.example.org
• it.example.org
• de.example.org

The above shows a typical division into sub-domains for the different language versions of the ‘example’ website. The third-level domain en is used to identify English-language content, while Spanish content can be found under the sub-domain es. The German-language part of the web project runs under the third-level domain de, and Italian users will find content in their native language when visiting the sub-domain it.

In theory, all domains below the top-level domain (TLD) are sub-domains of the preceding one, although in practice they are rarely called sub-domains. The domain name (second-level domain) is a sub-domain of the TLD, the third-level domain is a sub-domain of the second-level domain, and so on. For country-code second-level domains such as ‘.co’ in example.co.uk, the actual domain name (‘example’) becomes the third-level domain. A sub-domain of this would then be a fourth-level domain. In principle, the number of domain levels is unlimited. However, to be able to remember an Internet address well, it’s usually limited to three levels.

Knowledge of the hier­arch­ic­al structure of web addresses and domain ex­ten­sions can be helpful when it comes to finding the perfect domain. However, you should be careful not to com­plic­ate the design of your web project’s address un­ne­ces­sar­ily. In the end, a domain should always suit you and your project and make it as easy as possible for users as well as search engines to find your pages.

Finally, for this reason, we’ve sum­mar­ised some ele­ment­ary tips and tricks that will make choosing the right domain type and extension much easier.

Creating sub-domains doesn’t always make sense. A sub-division of your web address can also be confusing to web visitors, for example, if you generally don’t have a lot of content or if the sub-domain distracts too much from the actual domain name. Therefore, only decide to use an in­di­vidu­al third-level domain if you have a clear concept in mind for this. A specific sub-domain is useful for the following scenarios, among others:

• Dif­fer­en­ti­ation of different language versions
• Sep­ar­a­tion of content from other offers such as a service area, a blog, or a forum
• Marking a specific web service such as an app or an FTP server
• Operating an online shop in parallel to the website under the same second-level domain

When it comes to choosing the domain extension, it is not only the budget that plays a role. If the top-level domain does not match the content ori­ent­a­tion or style of your web project, this is not ne­ces­sar­ily negative from either a user’s or search engine’s per­spect­ive. For example, if you choose the generic top-level domain .shop, visitors and Google will assume that your project is a web shop. This may lead to negative reactions if this is not the case at all and you are neither involved in e-commerce or sta­tion­ary trade.

Even if you have found the right domain type from your point of view and are satisfied with the complete package including name and extension, you should not rush the re­gis­tra­tion of your web address. Ask friends and ac­quaint­ances or col­leagues for a serious and honest as­sess­ment of your domain. Outsiders will have a different per­spect­ive on the ap­pro­pri­ate­ness of your web address so be sure to take advantage of the op­por­tun­ity to get a second opinion to always be on the safe side when choosing domain type and domain name.