Web Architecture • Published August 14, 2026

URI vs URL vs URN: What Is the Difference? A Clear Developer Guide

Clear breakdown of URI vs URL vs URN with practical examples. Learn RFC 3986 definitions, locator mechanisms, and persistent resource names.

Demystify the classic Venn diagram of Uniform Resource Identifiers (URI), Locators (URL), and Names (URN) with real-world technical examples.

Frequently Asked Questions

Q1. Is a Data URI considered a URL?

Yes, according to the WHATWG specification, Data URIs are considered URLs because they define both the scheme (data:) and the method to access/decode the embedded payload.

Q2. What is a common example of a URN in software?

Common URN examples include urn:uuid:f81d4fae-7dec-11d0-a765-00a0c91e6bf6, urn:isbn:978-0132350884, and XML namespace identifiers like urn:oasis:names:tc:SAML:2.0:assertion.

Q3. Should I say URI or URL in API documentation?

In web APIs, when the endpoint address tells the client where to send HTTP requests (e.g. GET https://api.example.com/v1/users), URL is the most precise and commonly used term.