TLD Types & Differences

A gTLD (generic top-level domain) is intended for general use and is not restricted to a specific country, such as .com, .net, or .org. A ccTLD (country-code top-level domain) is a two-letter domain tied to a specific country or territory, like .uk for the United Kingdom or .de for Germany. ccTLDs are managed by national authorities and may have residency requirements.

A second-level domain (SLD) is the label immediately to the left of the TLD in a domain name. In 'example.com', 'example' is the SLD and '.com' is the TLD. The SLD is the part you choose and register. Some ccTLDs use structured second-level domains (like .co.uk) where '.co' acts as a functional SLD.

Sponsored TLDs (sTLDs) are a subset of gTLDs that are restricted to specific communities or industries, with a sponsoring organization overseeing eligibility rules. Examples include .edu (accredited US universities), .gov (US government entities), .mil (US military), and .aero (aviation industry). Registration in sTLDs requires proof of eligibility.

.com remains the most recognized and trusted TLD globally, making it the default choice for businesses with international audiences. However, if the .com version of your name is unavailable or expensive, alternatives like .co, .io (popular in tech), or a relevant new gTLD can work well — especially if the brand is memorable and consistent across channels.

.org was originally intended for non-profit organizations, while .com was for commercial entities. Today, both are unrestricted — anyone can register either. In practice, .org carries a perception of credibility and community trust that makes it popular for nonprofits, open-source projects, and advocacy groups, while .com is the dominant choice for businesses.

Geographic TLDs (geoTLDs) are new gTLDs representing cities, regions, or geographic entities — such as .london, .nyc, .paris, .tokyo, or .berlin. They were introduced under ICANN's New gTLD Program starting in 2014, allowing municipalities and regional authorities to operate their own TLD for local businesses and organizations. GeoTLDs differ from ccTLDs in that they represent sub-national geographic entities rather than sovereign countries or territories. Registration eligibility varies — some require a local address while others are open to anyone globally.

.arpa (Address and Routing Parameter Area) is the sole infrastructure TLD and is used exclusively for technical Internet operations — not for public website hosting. Its most common use is reverse DNS lookups: the 'in-addr.arpa' subdomain maps IP addresses back to hostnames (e.g., 1.0.0.127.in-addr.arpa maps to 127.0.0.1). It is managed by IANA on behalf of the IETF and is not available for general registration. The name comes from ARPANET, the precursor to the modern Internet.

A vanity TLD or brand TLD is a top-level domain owned and operated by a single company to represent its own brand — examples include .google, .apple, .amazon, .bmw, and .microsoft. These are obtained through ICANN's New gTLD Program at an application cost of $185,000 plus ongoing registry fees. Unlike public TLDs, brand TLDs are typically 'closed' — only the owning company can register domains under them. They allow corporations to create controlled, trusted URL spaces and memorable short links.

.com is a generic TLD (gTLD) managed by Verisign with no country or industry restrictions — it is the world's most recognized domain extension with over 160 million registrations. .co is the country-code TLD (ccTLD) for Colombia, but its registry (now operated by GoDaddy Registry) has actively marketed it globally as a short, versatile alternative to .com. Tech startups and businesses use .co when their preferred .com name is taken, interpreting it as shorthand for 'company' or 'commerce'. However, .co carries type-in traffic risk because users habitually type .com.

Many ccTLDs impose local presence or citizenship requirements. For example, .de (Germany) requires an administrative contact with a German address, .fr (France) requires an EU/EEA entity, .ca (Canada) requires Canadian citizenship, residency, or business incorporation, and .au (Australia) requires an Australian Business Number or trademark. In contrast, ccTLDs like .io, .co, .me, .tv, and .fm are 'open' and marketed globally without geographic restrictions. Always check the registry's eligibility policy before attempting to register a ccTLD.

Some countries structure their domain namespace using functional second-level domains beneath the ccTLD. In the UK, .co.uk is for commercial entities, .org.uk for non-profits, .ac.uk for academic institutions, and .gov.uk for government. Similarly, Australia uses .com.au, .org.au, .edu.au, and .gov.au. In these systems, the functional SLD (like 'co' or 'com') acts as a namespace qualifier analogous to gTLD categories, and the actual registrable name sits at the third level (e.g., 'mycompany' in mycompany.co.uk).

Yes — sponsored TLDs (sTLDs) are designed for and restricted to specific industries or communities. Examples include .aero (aviation industry), .museum (accredited museums), .coop (cooperatives), .edu (US universities), .mil (US military), and .gov (US government). New gTLDs have added more industry-focused extensions, though many are unrestricted in practice — for example .pharmacy requires NABP verification, and .bank and .insurance require financial regulatory compliance. Always check whether a specific TLD has eligibility requirements before registering.

.int is one of the original top-level domains and is reserved exclusively for intergovernmental organizations established by international treaties — such as the United Nations (un.int), NATO (nato.int), and the World Health Organization. Registration under .int is administered by IANA and is not available to the general public. It is one of the smallest and most exclusive TLDs, with only a few hundred registered domains. Only organizations that can demonstrate their establishment under an international treaty are eligible.

.su was delegated in 1990 as the ccTLD for the Soviet Union, which dissolved the following year. Unlike other defunct-state TLDs that were retired (such as .dd for East Germany), .su was never withdrawn and remains active today, operated by the Russian Institute for Public Networks. It has approximately 100,000 registered domains, many used by Russian internet users who prefer its Soviet-era connotations. ICANN has received requests to retire .su, but geopolitical complexities and existing registrant interests have kept it in the root zone.

A domain hack uses the TLD as part of the readable word or phrase. Commonly used TLDs for this purpose include .io (flexibil.io), .ly (bit.ly — Libya), .me (telepath.me — Montenegro), .to (wan.to — Tonga), .at (wh.at — Austria), .is (this.is — Iceland), .it (hack.it — Italy), .am (i.am — Armenia), .fm (last.fm — Micronesia), and .co (del.icio.us used .us). These creative registrations became popular because ccTLDs for small territories were often open to global registration at relatively low prices.

The longest TLDs currently delegated in the DNS root are 24 characters long — examples include .cancerresearch and .travelersinsurance. Under ICANN rules, new gTLD strings can be up to 63 characters in ASCII, though in practice approved TLDs rarely exceed 24 characters. Extremely long TLDs are uncommon because shorter extensions are more marketable and easier to type. The IDN ccTLD for Egypt (مصر.) is among the longest non-ASCII TLDs when encoded in Unicode.

.tel is a sponsored gTLD originally designed as a directory for contact information — phone numbers, addresses, and social profiles — stored directly in DNS TXT records rather than served through a traditional web server. It was conceived as a way to make contact data universally accessible without a website. In practice, adoption was limited, and the concept never gained mainstream traction. The .tel registry was eventually acquired by Telnic, and the TLD continues to exist but with very low registration volumes compared to popular gTLDs.

An ASCII-compatible encoding (ACE) TLD is the Punycode representation of an internationalized domain name (IDN) TLD — the form that is actually stored in the DNS root zone. Because DNS was originally designed for ASCII characters only, non-ASCII TLDs must be encoded using the 'xn--' prefix followed by an ASCII string. For example, the Arabic TLD for 'internet' (شبكة) becomes 'xn--ngbc5azd' in ACE form. Modern browsers display the Unicode label to users while internally using the ACE form for DNS lookups.

SSL certificates are issued at the hosting or CDN layer rather than by registries, so the TLD itself does not directly include an SSL certificate. However, some TLD registries bundle complimentary certificates or automatic HTTPS through partnerships. For example, Google Registry's .app and .dev TLDs require HTTPS by being included in the browser HSTS preload list — any domain on these TLDs must use SSL. Most hosting providers and CDN services (including Cloudflare and Netlify) provide free Let's Encrypt certificates automatically regardless of TLD.

.com is a globally unrestricted gTLD managed by Verisign and available to anyone worldwide. .com.au is a second-level domain under Australia's ccTLD (.au), reserved for Australian commercial entities — registration requires an Australian Business Number (ABN), trademark, or other Australian nexus. Because .com.au signals local Australian business presence, it is favored in Australia for consumer trust and local SEO. In 2022, au Domain Administration (auDA) also opened direct .au registrations as an alternative to the structured second-level system.

Yes — certain ccTLDs have been successfully repositioned as global generic extensions due to favorable connotations and open registration policies. .io (British Indian Ocean Territory) is ubiquitous in the tech industry as shorthand for 'input/output', .ai (Anguilla) has become the go-to TLD for artificial intelligence companies, .tv (Tuvalu) is widely used by streaming and video platforms, and .fm (Micronesia) is popular with podcasts and radio. From a technical standpoint, ccTLDs work identically to gTLDs for global users, though they carry the legal and policy framework of their home country's registry.

'GeoIP TLD' is not a formal ICANN category but is used informally to describe ccTLDs that trigger location-based signals in search engines. Google Search historically used ccTLDs as a country-targeting signal — a .de domain would be geotargeted to Germany in search results even without other configuration. Google has largely deprecated this automatic ccTLD signal in its algorithms, preferring explicit hreflang tags and Search Console geotargeting settings instead. However, user perception of local relevance from a familiar ccTLD remains a practical trust signal for regional audiences.

No TLDs are blocked in the global DNS root by ICANN itself, but individual countries and organizations may block or restrict access to certain ccTLDs at the network or firewall level. Additionally, ccTLDs of countries under international sanctions (such as .kp for North Korea or .ir for Iran) may face payment and service restrictions from registrars operating under US or EU sanctions law — making it practically difficult to register or maintain domains in those zones from sanctioned jurisdictions. Security tools and corporate firewalls often block domains under TLDs with high spam or malware associations.

ICANN and the IETF have reserved several TLD strings for documentation, testing, and development purposes that will never be delegated in the global DNS root. These include .test (for software testing), .example (for documentation examples), .invalid (for names that are guaranteed to be invalid), and .localhost (for local loopback addresses). Using these strings in development code, documentation, or tutorials is safe because they will never resolve on the public Internet — preventing accidental collisions with real registered domains.

As of 2025, IANA's root zone database contains over 1,500 top-level domains. This includes approximately 1,200+ new gTLDs introduced since 2014, around 316 country-code TLDs (two-letter ccTLDs), a small number of legacy gTLDs (.com, .net, .org, .info, .biz, .name, .pro), sponsored TLDs (.edu, .gov, .mil, .aero, etc.), and internationalized domain name (IDN) TLDs in non-Latin scripts. The count continues to evolve as new delegations occur and occasionally retired TLDs are removed. The IANA root zone database at iana.org is the authoritative source.