URI (Uniform Resource Identifier) is a string of characters used to identify a resource on the internet or a local network. A URI can be a URL (Uniform Resource Locator) that specifies how to access the resource, or a URN (Uniform Resource Name) that uniquely identifies the resource without specifying how to locate it. URIs are essential for linking resources in web development, APIs, and various other internet technologies.

Also known as: Resource identifier, Web identifier, Internet resource locator, Address string, Uniform identifier.

Comparisons

• URI vs. URL: A URL is a type of URI that includes both the resource's location and the protocol used to access it, whereas a URI can be either a URL or a URN, which may not include the access method.

• URI vs. URN: While a URI can refer to any type of resource identifier, a URN (Uniform Resource Name) is specifically used to name a resource uniquely without defining its location or how to retrieve it.

Pros

• Flexibility: URIs can identify both local and remote resources, making them versatile in various applications, from web addresses to database records.

• Standardization: Provides a consistent and standardized way to reference resources, which is crucial for interoperability across different systems and platforms.

• Scalability: URIs can be used in various contexts, from web URLs to identifiers in databases and APIs, making them scalable for different use cases.

Cons

• Complexity: Understanding the distinction between URLs, URNs, and URIs can be confusing, especially for those new to web technologies.

• Potential for Misuse: Incorrectly formatted URIs can lead to errors in resource identification or retrieval, potentially breaking links or causing failures in applications.

• Security Concerns: Like URLs, URIs can be manipulated for malicious purposes, such as phishing or unauthorized access to resources.

Example

The URI mailto:[email protected] identifies an email address and specifies the protocol (mailto) used to interact with it. Unlike a URL, this URI doesn’t provide a location for a web resource but rather an identifier for an email communication.