What Is the Difference Between URL and URI?

Even though most people aren’t going to need to know the difference between a URL and a URI, it really matters in a few specific situations! 

Understanding the difference between URL vs. URI is important in a number of contexts, especially for web developers, IT professionals, and anyone working with internet technologies. 

URL vs. URI: What’s the difference?

Let’s start by going over the differences between these two concepts. 

URI stands for Universal Resource Identifier, and URL stands for Universal Resource Locator. The main difference between them is that the “I” in URI can point to a resource’s name, location, or both. The “L” in URL means that it only points to the location of a specific resource. 

In short, a URL is a type of URI. 

Understanding URIs

Here are some important things to know about URIs:

• URI stands for “Uniform Resource Identifier”
• Under the category of URI, you can also have URNs (Uniform Resource Numbers) and URLs (Uniform Resource Locators)
• Components of a URI include scheme, authority, path, and query
• URI example: ISBN 0-06-443017-0 
• Typically used for things like XML, tag library files, JSTL files, and XSTL files
• The URI scheme may be protocol, specification, or designation (HTTP, file, data, etc.)

Understanding URLs

Here are the basic facts about URLs: 

• URL stands for “Uniform Resource Locator”
• It is part of a subcategory (subset) of URIs
• The URL’s job is to identify the web address or location of a unique internet resource
• Components of a URL include a domain name and port
• Sample URL: https://whatismyipaddress.com/
• The main purpose of a URL is to direct internet users to the correct web page
• The scheme is a protocol (such as HTTP and HTTPS)

What about URNs?

URN stands for “Universal Resource Name.” It is location-independent, which means that the resource is identified permanently by the URN. Even if the data associated with the resource is moved to another location, the URN remains the same and effectively redirects to the resource. 

The scheme that URN uses to differentiate resources from another has at least three elements, which are typically: 

• The prefix urn, which is the scheme specification
• The NID, which is a namespace identifier that is registered with the Internet Assigned Numbers Authority (IANA). NID may include numbers, letters, or a colon that follows a hyphen.
• The namespace-specific string (NSS), which identifies the resource. The NSS may include ASCII codes, special characters, and digits. 

Please note: this is a general overview of the elements that are involved in the URN scheme. The specific syntax and rules for constructing a URN will vary based on the type of resource it is, any namespace-specific guidelines, and the NID. 

This structure scheme allows URNs to unambiguously identify resources without relying on a central authority or location. It is a very flexible scheme that can be extended to identify any type of online resource.

When is it important to understand URI vs URL?

Here are some of the circumstances in which it is useful to understand the differences between URI and URL. 

Web development

Web developers need to work with both URIs and URLs when they are creating websites and web applications. They have to understand the structure of URLs to build links, handle routing, and manage resources correctly.

API design

If you are designing an API (Application Programming Interface), you need to choose between using URIs or URLs to identify resources and endpoints. This choice affects how clients access and interact with your finished product. 

Network configuration

Network administrators and IT professionals often deal with configuring resources using both URIs and URLs, as well as URNs. Understanding these concepts help them to set up proper access controls and routing. 

Data integration

When you are integrating data from multiple sources and/or systems, you need to know how to form and handle URIs and URLs, as this is important for the efficiency of data retrieval and exchange. 

Cybersecurity

Cybersecurity analysts may need to understand URIs vs. URLs to effectively monitor network traffic for anomalie and block malicious requests without blocking legitimate traffic. They may also need to extract and analyze URIs and URLs from surveillance data in order to infer relationships between persons of interest, identify access to restricted online resources, and attribute cyber attacks to the correct party. 

Law enforcement

For law enforcement, analyzing URLs is critical for investigating cybercrimes. Domain names can identify perpetrators, paths point to specific scam/phishing pages, parameters reveal information theft techniques, URL patterns tie crimes together, and historical URL data provides evidence to uncover leads and build timelines for prosecution. 

Developing expertise in dissecting and analyzing URL and URI components enables officials to connect the dots, attribute attacks, and gather digital evidence during cybercrime investigations.

Investigate spoofing attacks

URI/DNS spoofing attacks try to disguise malicious sites as legitimate websites. Being able to inspect a URI for credibility helps to investigate and avoid spoofing attacks. 

Protect classified information

Some classified systems on government networks use custom internal URI schemes for accessing resources; being able to understand these locators helps to maintain security. URI patterns can be signatures for identified classified documents or assets that have been leaked online. 

Security and privacy

Corporations can improve their data privacy methods by having a strong knowledge of URIs and URLs. Securing user data is important, and improper handling of URIs and URLs can lead to privacy breaches from vulnerabilities like open redirects or cross-site scripting (XSS) attacks. 

Copyright matters

A strong understanding of the distinctions between URIs and URLs might be relevant when dealing with copyright issues, licensing, or intellectual property disputes related to online resources.

Our Final Word on URL vs. URI

Grasping the distinction between URLs and URIs is about much more than just understanding some technical details. For those who work in very specific areas, it is a fundamental understanding that can greatly impact your work! 

From web development and network configuration to cybersecurity and law enforcement, the ability to discern between these identifiers empowers professionals in these areas to navigate complex challenges with precision and accuracy.