What Is a URI?

What is URI?

URI stands for "Uniform Resource Identifier." It is a string used to identify or point to a resource. This resource can be a file, a web page, or a service. URI ensures that resources are uniquely identified on a global scale.

A URI can look like this:

This example is a URI that identifies a web resource. However, URI does not only cover web addresses; email addresses and other types of resources can also be URIs.

What is URL?

URL stands for "Uniform Resource Locator." It is a type of URI that specifies the location of a resource and how to access it. URL is one of the most common formats used to specify the address of a resource.

A URL consists of the following components:

• Protocol: The communication method used to access the resource. For example, https.
• Domain Name: The address of the server where the resource is located. For example, www.example.com.
• Path: The directory used to access a specific resource on the server. For example, /index.html.

An example of a URL can be:

What is the Difference Between URI and URL?

URI and URL are often used interchangeably, but there are important differences between them:

• Definition: URI is a general term that identifies or points to a resource. URL is a subset of URI that specifies the location of the resource.
• Focus: URI focuses on identifying the resource. URL focuses on how to access the resource.
• Scope: Every URL is a URI, but not every URI is a URL. For example, a URN (Uniform Resource Name) is a type of URI that identifies a resource but does not specify its location.

Example:

• URI:urn:isbn:0451450523 (Identifies a book but does not specify its location.)
• URL:https://www.example.com/book/0451450523 (Specifies the location of a book.)

Should I Use URL or URI?

Which term you should use depends on what you want to express:

• If you want to specify the location of the resource: You can use the term URL.
• If you want to generally identify the resource: The term URI is more appropriate.

In web development and daily use, the term URL is more common. However, in technical documents and standards, URI is often preferred. For example:

• If you specify a web address: Using "URL" is appropriate.
• If you want to express both the identifier and locator function of the resource: "URI" should be preferred.

In general, URL is better known and more widely used in modern usage. However, URI is a broader term and encouraged for correct technical use.