What is URL?
URL is a specific type of URI that provides the complete address to locate a resource on the internet, including the protocol, domain, path, and optional parameters.
Quick Facts
| Full Name | Uniform Resource Locator |
|---|---|
| Created | 1994 by Tim Berners-Lee (RFC 1738) |
| Specification | Official Specification |
How It Works
URL is the fundamental addressing mechanism of the World Wide Web, specifying both the location and access method for web resources. A URL consists of several components: the scheme (protocol like http or https), host (domain name or IP address), optional port number, path to the resource, query string for parameters, and fragment identifier for page sections. URLs enable browsers and applications to retrieve resources from web servers, making them essential for navigation, linking, and API communication across the internet.
Key Characteristics
- Specifies both resource location and access protocol
- Contains scheme, host, port, path, query, and fragment components
- Supports various protocols including HTTP, HTTPS, FTP, and mailto
- Domain names are case-insensitive while paths may be case-sensitive
- Query parameters use key=value pairs separated by ampersands
- Fragment identifiers reference specific sections within a resource
Common Use Cases
- Navigating to web pages in browsers
- Making HTTP requests to REST APIs
- Embedding images and media in web pages
- Sharing links to specific content
- Configuring webhooks and callback endpoints
Example
Loading code...Frequently Asked Questions
What are the main parts of a URL?
A URL consists of: scheme (protocol like https), host (domain name), port (optional, like :8080), path (resource location), query string (parameters after ?), and fragment (section after #). Example: https://example.com:8080/path?query=value#section
What is the difference between URL and URI?
A URL is a specific type of URI that provides the complete address to locate and access a resource, including the access method (protocol). URI is the broader term that includes both URLs (locators) and URNs (names).
Are URLs case-sensitive?
The domain name part is case-insensitive (example.com = EXAMPLE.COM), but the path and query string are typically case-sensitive on Unix-based servers. Windows servers are usually case-insensitive for paths.
What is the maximum length of a URL?
While there's no official limit in the specification, practical limits exist. Internet Explorer historically limited URLs to 2,083 characters. Most modern browsers support much longer URLs, but keeping URLs under 2,000 characters ensures compatibility.
How do query parameters work in URLs?
Query parameters follow the ? character as key=value pairs separated by &. For example, ?name=John&age=30 passes two parameters. Values with special characters must be URL-encoded to ensure proper parsing.