Do you know the difference between a URI, URL, and slug?
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The terms URI, URL, and slug are often mixed up, but they have distinct meanings. Using the correct one makes communication clearer when working with links, routing, and CMS content.
What is a URI?
A URI (Uniform Resource Identifier) is the broadest concept.
It identifies a resource, either by its location or by name.
Examples:
- mailto:info@ssw.com.au
A URI does not have to be a web link.
What is a URL?
A URL (Uniform Resource Locator) is a type of URI that tells you where a resource is and how to access it.
It includes:
- Protocol
- Domain
- Path
Example:
Most links you share are URLs.
What is a slug?
A slug is the human-friendly part of the URL that identifies a specific page.
Slugs should be:
- Short
- Readable
- SEO-friendly
Example - the slug is at the end of a full URL (see bold):
- https://www.ssw.com.au/rules/seo-checklist
Slugs are commonly used in CMS tools like TinaCMS and WordPress.
Figure: The slug field in TinaCMS defines the human-friendly part of the URL
When should you use each term?
Use **URI **when speaking technically about identifiers. E.g. APIs, specifications.
Use URL when referring to a full web address. E.g. links in pages, emails, or documentation.
Use slug when referring to the editable part of a page path. E.g. in CMS, routing, or SEO.
Why this matters
Using the correct term:
- Improves communication between devs, designers, and content editors
- Avoids confusion in requirements and documentation
- Aligns with how tools like TinaCMS and WordPress work
“Change the URL.” (when you only mean the slug)
“Paste the URI here.” (when you mean a normal link)
❌ Figure: Bad example - Using the wrong terms
“Update the slug to make it more SEO-friendly.”
“Send me the URL to the page.”
“This API returns a URI.”
✅ Figure: Good example - Using the correct terms
Figure: Figure: URI is the umbrella term, URL is the full address, and slug is the readable end of the path