The complete guide library

Every TLD & domain guide, in one place.

This is the full library of plain-English, source-backed guides on tlddomain.us. Start with the basics, compare extensions head to head, learn how to choose and register a domain, or dig into the technical machinery of the Domain Name System. Everything here is grouped by topic so you can read in order or jump straight to your question.

▲ What this library covers

These guides explain top-level domains (TLDs) and domain extensions from every practical angle: what they are, how the main types differ, how to pick the right one for a business, blog or startup, how registration and WHOIS work, and how the wider DNS hierarchy fits together. They are written for clarity, kept current, and cite primary sources such as IANA and ICANN.

Not sure where to begin? If domains are new to you, read what is a TLD first, then TLD vs domain name and gTLD vs ccTLD. If you already know the basics and just need to pick an extension, jump to how to choose a domain extension or one of the “best TLD for…” guides below. Each guide ends with sources and links to closely related topics, so you can follow the thread wherever your question leads.

Last updated · Independently published by Mustafa Bilgic · Sources: IANA, ICANN, registry operators

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Basics & definitions

Categories

TLD types

Head to head

Extension comparisons

Extension guides

Popular extensions explained

The .org domain explained

The nonprofit-associated TLD that anyone can register — meaning and rules.

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The .net domain explained

From network infrastructure to the leading alternative when .com is taken.

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The .xyz domain explained

The big, cheap, meaning-neutral new gTLD used by Alphabet and Web3.

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The .dev domain explained

Google's developer TLD — and why every .dev site must use HTTPS.

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The .app domain explained

A secure-by-default extension built for apps and software products.

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The .me domain explained

Montenegro's code, sold worldwide for portfolios and personal sites.

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The .tech domain explained

A descriptive extension for technology companies, products and events.

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The .shop domain explained

A purpose-built extension for online stores and e-commerce brands.

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The .store domain explained

A descriptive retail extension for shops, brands and online sellers.

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The .online domain explained

A broad, memorable new gTLD for any business or project on the web.

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The .site domain explained

A flexible, generic extension for websites of every kind.

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The .blog domain explained

The descriptive TLD made for bloggers, writers and publications.

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The .info domain explained

One of the original new gTLDs, built for informational websites.

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The .biz domain explained

A business-only extension, who can register it, and when it fits.

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The .club domain explained

A community-focused TLD for groups, clubs, teams and memberships.

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The .live domain explained

An extension built for streaming, events and real-time content.

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Practical guides

How-to & registration

Make the right call

SEO & choosing

Under the hood

Technical & governance

How the DNS hierarchy works

From the root zone down to your domain: how name resolution happens.

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Who controls TLDs?

ICANN, IANA and registries — who sets policy and runs each extension.

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What is DNS?

The internet's address book that turns names into IP addresses.

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How resolution works

The step-by-step journey from your browser to the authoritative server.

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What is a name server?

The machines that answer DNS queries — authoritative vs recursive.

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What are root servers?

The 13 identities at the top of DNS, and how anycast scales them.

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What is an FQDN?

The complete, unambiguous name of a host — every label up to the root.

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What is a wildcard domain?

How *.example.com matches all subdomains in DNS and SSL at once.

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Punycode explained

How Unicode domains become the xn-- ASCII the DNS understands.

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What is ICANN?

The non-profit that coordinates domain names and sets TLD policy worldwide.

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What is IANA?

The authority that maintains the root zone and the official list of TLDs.

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What is DNSSEC?

How cryptographic signatures protect DNS answers from tampering.

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How new gTLDs are created

Inside ICANN's application process for launching a brand-new extension.

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History of domain names

From the first .com in 1985 to today's 1,500+ extensions.

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Quick answers

Frequently asked questions

Frequently asked questions

Where should I start with these guides?

If you are new to the subject, begin with “What is a TLD?” then “TLD vs domain name” and “gTLD vs ccTLD.” From there, move to choosing and registering an extension. The guides are grouped by category so you can jump straight to what you need.

Are these guides free to read?

Yes. Every guide on tlddomain.us is free, independently published, and supported by advertising. There is no paywall and no sign-up required.

How current is the information?

Each guide carries a “last updated” date and cites primary sources such as IANA and ICANN. Domain facts and figures are described as approximate where they change over time, and we revise the guides as the landscape evolves.

Do you sell domains?

No. tlddomain.us is an educational reference about top-level domains and domain extensions, not a registrar. We explain how registration works and what to look for, then you register through a registrar of your choice.

Registration, transfers & advanced topics

Ready to dive in?

Start with the fundamentals, then work toward choosing and registering the perfect domain.

Read: What is a TLD? →