URI vs. URL: What’s the Difference?

In the world of web development, the terms “URI” and “URL” are often used interchangeably, leading to confusion and misunderstanding among developers and other tech professionals. While both of these concepts refer to ways of identifying resources on the internet, they have important differences that are critical to understand for effective web development. URI, or Uniform Resource Identifier, is a string of characters that uniquely identifies a resource, while URL, or Uniform Resource Locator, is a type of URI that specifically identifies the location of a resource on the internet. In this article, we will explore the differences between URI vs. URL, including their uses, formats, and implications for web development and digital communication. By the end of this article, you will have a better understanding of these essential concepts and how to use them effectively in your work.

What is a URI?

URI stands for “Uniform Resource Identifier”. It is a string of characters that uniquely identifies a resource, such as a web page, a file, or a piece of data, on the internet. URIs are used to locate and retrieve resources over a network, and they can be used by a variety of applications, including web browsers, email clients, and file transfer programs. A URI can be broken down into three main parts: the scheme, which identifies the type of protocol used to access the resource, such as “http” or “ftp”; the authority, which specifies the location of the resource, such as the domain name or IP address; and the path, which identifies the specific resource being requested. A URI can also include additional components, such as query parameters or fragments, which provide additional information about the resource or how to access it.

An example of a URI that contains various components is “foo://example.com:8042/over/there?name=ferret#nose”. This URI includes a scheme name, authority, path, query, and fragment. However, it’s important to note that a URI doesn’t necessarily have to contain all of these components to be valid. At minimum, a URI must have a scheme name and a file path, which can be empty.

Types of URI

URIs can be divided into two main types: URNs and URLs.

A Uniform Resource Name (URN) is a type of URI that follows the “urn” scheme and provides a persistent, location-independent identifier for a resource. This means that a URN can identify the same resource over time, even if its location changes. An example of a URN is provided by the RFC 3986: urn:oasis:names:specification:docbook:dtd:xml:4.1.2.

On the other hand, a URL is a type of URI that is location-dependent and may not provide persistent identification for a resource. URLs do not follow the “urn” scheme and are typically used to specify the location of a resource on the internet. This means that a URL may not identify the same resource over time if its location changes.

With this understanding of URIs, URNs, and URLs, let’s take a closer look at URLs in the following section.

A URL, or Uniform Resource Locator, is a specific type of URI that provides a location-based address for a resource on the internet. URLs are used to identify and retrieve resources, such as web pages, images, videos, or other types of files, and are commonly used in web browsers and other applications that access the internet.

A URL consists of several components that provide information about the location of the resource, including:

Scheme: Indicates the protocol used to access the resource, such as “http” or “https”.
Authority: Identifies the domain name or IP address of the server hosting the resource.
Path: Specifies the location of the resource on the server.
Query: Provides additional information about the resource that can be used by the server to process the request.
Fragment: Specifies a specific location within the resource, such as a particular section of a web page.

Here are some more examples of URLs:

https://www.google.com/search?q=URL+examples&oq=URL+examples&aqs=chrome.0.35i39l2j0l4j46j69i60.3554j1j4&sourceid=chrome&ie=UTF-8 – This URL points to a Google search results page for the query “URL examples”. The scheme is “https”, the authority is “www.google.com“, the path is “/search”, and the query parameter is “q=URL+examples”.
https://www.amazon.com/Kindle-eBooks/b?ie=UTF8&node=154606011 – This URL points to the Kindle eBooks section on the Amazon website. The scheme is “https”, the authority is “www.amazon.com“, the path is “/Kindle-eBooks/b”, and the query parameter is “node=154606011”.
https://www.youtube.com/watch?v=dQw4w9WgXcQ – This URL points to the official music video for Rick Astley’s “Never Gonna Give You Up” on YouTube. The scheme is “https”, the authority is “www.youtube.com“, the path is “/watch”, and the query parameter is “v=dQw4w9WgXcQ”.
https://www.nytimes.com/2022/04/07/business/economy/unemployment-claims-coronavirus.html – This URL points to a New York Times article about unemployment claims during the COVID-19 pandemic. The scheme is “https”, the authority is “www.nytimes.com“, and the path is “/2022/04/07/business/economy/unemployment-claims-coronavirus.html”.

These examples illustrate how URLs are used to provide a specific address for various types of resources on the internet.

What is the difference between URIs and URLs?

The main difference between URIs and URLs is that URIs are a broader category that includes both URLs and URNs, while URLs are a specific type of URI that provides a location-based address for a resource on the internet.

A URI, or Uniform Resource Identifier, is a string of characters that identifies a name or a resource on the internet. It can be further divided into two subcategories: URLs and URNs.

A URL, or Uniform Resource Locator, provides a location-based address for a resource on the internet, typically using a specific protocol, such as HTTP or FTP. URLs are used to locate resources such as web pages, images, videos, or other types of files. For example, https://www.example.com/index.html is a URL that points to a specific web page on the example.com domain.

A URN, or Uniform Resource Name, on the other hand, provides a persistent, location-independent name for a resource on the internet, regardless of its current location. URNs are designed to be long-lasting, so that the resource can still be accessed even if its location changes. For example, urn:isbn:0-486-27557-4 is a URN that identifies a specific book by its ISBN number.

In summary, while both URIs and URLs are used to identify resources on the internet, URLs are a specific type of URI that provide a location-based address for a resource, while URNs provide a persistent name for a resource regardless of its location.

FAQ About URIs vs. URLs?

Here are some frequently asked questions about URIs vs. URLs:

Q: What is a URI?

A: A URI, or Uniform Resource Identifier, is a string of characters that identifies a name or a resource on the internet. URIs can be further divided into two subcategories: URLs and URNs.

Q: What is the difference between URL vs. URI?

A: A URL, or Uniform Resource Locator, is a specific type of URI that provides a location-based address for a resource on the internet, typically using a specific protocol, such as HTTP or FTP. In contrast, a URI is a broader category that includes both URLs and URNs.

Q: What is the difference between URL vs. URN?

A: A URL provides a location-based address for a resource on the internet, while a URN, or Uniform Resource Name, provides a persistent, location-independent name for a resource on the internet, regardless of its current location.

Q: What are some examples of URLs?

A: Some examples of URLs include https://www.google.com, https://www.amazon.com, and https://www.youtube.com/watch?v=dQw4w9WgXcQ.

Q: What are some examples of URNs?

A: Some examples of URNs include urn:isbn:0-486-27557-4 (which identifies a specific book by its ISBN number) and urn:oasis:names:specification:docbook:dtd:xml:4.1.2 (which identifies a specific version of the DocBook XML specification).

Q: Are all URLs also URIs?

A: Yes, all URLs are also URIs, since URLs are a specific type of URI.

Q: Are all URNs also URIs?

A: Yes, all URNs are also URIs, since URNs are a specific type of URI.

Q: Why is it important to understand the difference between URIs and URLs?

A: Understanding the difference between URIs and URLs can help clarify how resources are identified on the internet, and can help developers and web designers create better, more flexible systems for accessing and managing resources. It can also help prevent confusion or errors when working with different types of resources on the internet.