What is a domain name?

A domain name is made of labels separated by dots, but not every label has the same meaning. The part most people care about is the registrable domain, which is the boundary where ownership usually starts after public suffix rules are applied.

Subdomains, second-level domains, top-level domains, and public suffixes can all look similar at a glance. Parsing them correctly matters when you are validating URLs, grouping hosts, or extracting the part a user actually controls.

Tool description

This tool parses a domain and splits it into its main components. It shows the registrable domain, subdomain, second-level domain, top-level domain, and whether the input matches a public-suffix-listed structure.

It is helpful when you need a quick explanation of how a hostname is organized without manually checking suffix rules.

Examples

  • www.example.com
  • mail.support.example.co.uk
  • blog.example.io

Features

  • Instant parsing as you type
  • Copyable output fields for each domain part
  • Validation feedback for malformed input

How it works

The tool uses public suffix rules to decide where the registrable domain starts and ends. That means the result depends on the suffix data, not just on the number of dots in the input.

If a domain uses an unusual or private suffix, the parser follows the library’s rule set rather than guessing.