# URL

Category: [Technical SEO](https://seo-geo-glossary.com/en/glossary/category/technical-seo/) › [URLs & domains](https://seo-geo-glossary.com/en/glossary/category/technical-seo/urls-domains/) · Also known as: web address, Uniform Resource Locator

A **URL** (Uniform Resource Locator) is the address of a unique resource on the web, such as an HTML page, an image or a document. Search engines identify every page they crawl and index by its URL.

## What are the parts of a URL?

```txt
https://example.com:443/guides/url?lang=en#parts
```

- **Scheme** (`https`) names the protocol.
- **Authority** (`example.com:443`) holds the domain, optionally with a subdomain and a port. The port is usually omitted.
- **Path** (`/guides/url`) shows where the resource sits on the server.
- **Query string** (`?lang=en`) carries key and value pairs for extra data. Multiple pairs are joined with `&`.
- **Fragment** (`#parts`) points to a section within the page and is never sent to the server (MDN).

A URL can be absolute, with scheme and domain, or relative to the current page, for example `/guides/url`.

## What does Google say about URLs?

Google lists these recommendations:

- Use readable words rather than long ID numbers.
- Separate words with hyphens, not underscores.
- Keep casing consistent, because Google Search treats URLs as case sensitive. `/APPLE` and `/apple` are different URLs.
- Use `=` between key and value and `&` between parameters.
- Do not use fragments to change page content, since Google Search generally does not support them.
- Percent-encode non-ASCII characters in `href` attributes and avoid session IDs in URLs.

## Example

`example.com/wiki/Aviation` is easier to interpret than `example.com/index.php?topic=42&area=3a5ebc944f41daa6f849f730f1`. Both examples come from Google's documentation.

## Common mistakes

- **Inconsistent casing.** Google treats `/APPLE` and `/apple` as different URLs, so both variants become separate addresses for the same page.
- **Underscores instead of hyphens.** Google recommends hyphens between words.
- **Fragments to tell content apart.** Google advises against using `#` to distinguish different content.
- **Session IDs in the URL.** They create many URLs for the same content and put load on crawling.

## Frequently asked questions

**What is the difference between a URL and a link?**
A link is the clickable reference on a page. The URL is the address it points to.

*Diagram: Anatomy of a URL.* A URL broken into its parts. RFC 3986 defines scheme, host, path, query and fragment. Only the browser evaluates the fragment after #, it is not sent to the server.

## Related terms

- [URL structure](https://seo-geo-glossary.com/en/glossary/url-structure/index.md)
- [SEO-friendly URL](https://seo-geo-glossary.com/en/glossary/seo-friendly-url/index.md)
- [URL parameters](https://seo-geo-glossary.com/en/glossary/url-parameters/index.md)
- [URL case sensitivity](https://seo-geo-glossary.com/en/glossary/url-case-sensitivity/index.md)
- [Dynamic URL](https://seo-geo-glossary.com/en/glossary/dynamic-url/index.md)
- [Fragment identifier](https://seo-geo-glossary.com/en/glossary/fragment-identifier/index.md)

## Sources

- [What is a URL? – MDN Web Docs](https://developer.mozilla.org/en-US/docs/Learn_web_development/Howto/Web_mechanics/What_is_a_URL)
- [URL structure best practices for Google Search – Google Search Central](https://developers.google.com/search/docs/crawling-indexing/url-structure)
- [RFC 3986 – Uniform Resource Identifier (URI): Generic Syntax – IETF](https://www.rfc-editor.org/rfc/rfc3986)

---

Last updated: October 8, 2026
URL: https://seo-geo-glossary.com/en/glossary/url/