What is a URL?
A URL (Uniform Resource Locator) is the "full address" that points to any page or image on the web. Something like https://digitalkodomo.jp/blog/2026-04-25-ai-game-event.html is a URL. Breaking it into parts, you can see several distinct components.
What is a domain?
A domain refers only to the "address part" of a URL. Like digitalkodomo.jp, it takes the form "subdomain.domainname.TLD." The rightmost part — .jp, .com, .org — is the Top-Level Domain (TLD). "digitalkodomo" is the domain name. Something like "www" would be a subdomain.
Why domains are needed
Servers on the internet are actually identified by IP addresses (numbers like 192.0.2.1). But remembering numbers is hard, so there's a system that converts human-friendly names into those numbers — DNS (Domain Name System). When you type a domain in a browser, a DNS server tells it "this domain is at this IP address." Think of it like a phone book.
Types of domains
How to register a domain
Domains are rented annually from companies called registrars — like Namecheap, Cloudflare Registrar, or GoDaddy. Prices vary by TLD and timing; some are cheap in year one and expensive at renewal. Once registered, you can use it as your site's address freely — but teens should get a parent/guardian's consent before registering.
Practical tips
If you're serious about running a portfolio or blog long-term, getting a custom domain early is worthwhile. Registering something close to your nickname or project name — and keeping the same URL through middle school, high school, and university — means you never need to move your work. Avoid strings that reveal too much personal info, and pick a name you'll still want years from now.
Once you have a domain, you can also learn DNS settings. Understanding the difference between A records, CNAMEs, and MX records reveals how websites, subdomains, and email all work. A good first exercise is connecting your custom domain to GitHub Pages or Cloudflare Pages — easy to reverse if something goes wrong.
Common pitfalls
- Including your full real name in the domain. a nickname is safer.
- Choosing a "first year $1" deal without noticing the price jumps to $40+ in year 2. Always check the renewal cost.
- Registering a famous brand or celebrity name as a domain (trademark disputes can result).
How will this help you in the future?
Domain mechanics come up everywhere in IT work — web development, DNS setup, email management, internal systems. "I registered and operated my own domain" is a fundamental piece of engineering experience. Later in life, being able to diagnose "why isn't this email being delivered?" at the DNS level will make you invaluable at work.
When troubleshooting, you need to distinguish between a wrong URL path, an expired domain, a DNS propagation delay, and a down server — each has a different fix. Being able to tell these apart increases your credibility in web development.
What you can do today
- Copy a URL from a site you use and break it into "protocol," "domain," and "path."
- Search for the domain name you'd want at a registrar like Namecheap (free to search).
- Talk with a parent/guardian and, if serious about running a site, register a custom domain.
Summary
Check Domain vs URL is?