A Uniform Resource Identifier ( URI ) is an identifier and consists of a string identifying an abstract or physical resource is used. URI ‘s are used for identification of resources (such as websites , other files, calling web services , but also, for example, e-mail recipients) in the Internet and there, especially in Web use.

Originally, Tim Berners-Lee the concept in 1994 in RFC 1630 as a Universal Resource Identifier one. Only later appeared then in official W3C documents, the resolution uniform on. For this reason, universal occasionally – even in the scientific literature – the first part of their name called as.

URIs can be used as a string (encoded with a character set ) into digital documents, especially those in HTML format or incorporated by hand on paper to be written. A reference from a Web page to another is called a hyperlink or just link.

An extension of the only printable ASCII -character- URIs are Internationalized Resource Identifiers (IRIs).