The acronym URL stands for "Uniform Resource Locator". It represents an address that guides you to a specific file on a server, accessible via network protocols like http, https, or ftp. Essentially, a URL enables precise identification and retrieval of a resource using a specific network protocol. In everyday language, URLs are often referred to as internet addresses or web addresses, typically associated with websites and accessed through web browsers.
Every website can be accessed using an IP address. However, manually entering a long string of numbers each time you want to visit a website would be impractical. In the 1990s, as the internet expanded, researcher Tim Berners-Lee worked on establishing a standard for accessing documents online. This effort led to the development and publication of the RFC 1738 standard in 1994, initially known as the “Universal Resource Identifier”. That same year, the “Uniform Resource Locator” subtype was introduced, giving rise to the internet addresses we recognize today.
A basic URL consists of three components: the protocol (https://, ftp://), the domain or server name (www.domain.com), and the file path (/directory/file.html). The file path can include multiple directory levels.
When files are accessed via another server instead of a web browser, a URL might look like this:
https://peter:[email protected]:8080/index.html
This URL includes the protocol, user credentials, the host (www.example.com), and the port (8080) needed for data retrieval.
Within an HTML document, relative URLs can be used, omitting the protocol and server name. Only the directory and file name are specified, such as /directory/file.html. When a relative URL is clicked, the browser defaults to the domain server's address where the link is located.
To avoid errors in URL interpretation, only certain characters are allowed in URL encoding, using the ASCII character set. This ensures characters like ampersands (&) or hyphens are correctly interpreted by browsers. If a URL contains an uncoded space, the browser may misread it. Browsers can correctly interpret URLs by converting ASCII characters into a percentage format, which is particularly important for special characters like umlauts or ß.
Such issues often occur if article headlines are automatically used in URLs by CMS systems. Coded URLs in the source code can be identified using the MIME type.
URL coding also reserves specific characters for functions within the URL. Reserved characters include:
Non-reserved characters include numbers (0-9) and letters (A-Z, a-z), along with symbols like - _ ~, which can have varying meanings based on programmer preference.
The terms domain and URL are often used interchangeably today, but they differ significantly. A URL consists of the domain name and the path within the World Wide Web, while a domain is merely the name within the Domain Name System (DNS). Domains can be chosen relatively freely and are associated with a top-level domain.
For example, the URL of our site is “https://www.searchmetrics.com”, whereas our domain is simply “searchmetrics.com”.
Historically, including keywords in a URL was crucial for search engine optimization (SEO). This practice helped webmasters achieve better rankings with keyword-rich domains on search engines like Google. The idea was that relevant keywords in the URL could better indicate the topic and thus enhance rankings. Indeed, keywords in URLs can assist both users and search engines in understanding the website's content.
Short URLs can simplify orientation, although Google can effectively process URLs exceeding 1,000 characters.