Definition: XRI

(EXtensible Resource Identifier) An OASIS standard for a high-level naming/identification system for individuals, businesses, communities, services and data on the Internet. XRI, along with XDI, a general-purpose data interchange protocol based on XRI, were developed to create the "Dataweb," which enables the Web to operate like a global database.

One of the goals XRI and XDI share with the "Semantic Web" is to improve Web searching. Rather than returning thousands of links, a fully implemented Dataweb and an XRI-enabled search engine would return a smaller set of more meaningful links. Another goal of XRI and XDI is to enable Web services to discover and interact with each other more consistently. In real life the same entity can have many names, and XRI and XDI support synonyms and synonym mapping services.

I-Names and I-Numbers
There are two types of XRIs: i-names and i-numbers. I-names are people-friendly names that are easy to remember, and which can change over time, just like a person or company may change its name. I-numbers are like serial numbers: persistent identifiers that never change. In general, i-names point to i-numbers, so people can use easy-to-remember identifiers that machines can translate into stable, long-term identifiers for the resource they identify.

The i-number in turn points to a standardized XML document that contains specific current addresses for a resource such as URLs, telephone numbers and postal addresses. When an XRI-identified resource is located, an XRI-enabled browser bookmarks both its i-name and i-number. If a bookmarked resource changes its i-name, the user's bookmark is still valid because of the i-number. See i-name for more details.

OpenID
In 2007, the OpenID authentication system adopted XRIs as an option for creating OpenID usernames. When an XRI i-name is handed to an OpenID website, the i-name is resolved into the URL of the OpenID provider (see OpenID). See XDI.