Wikidata

Wikidata is a collaboratively edited, multilingual knowledge base operated by the Wikimedia Foundation. Launched on 29 October 2012, it was the first new Wikimedia project since 2006, developed by a team based at Wikimedia Deutschland in Berlin with initial funding (about €1.3 million) from the Allen Institute for AI, the Gordon and Betty Moore Foundation, and Google. Its design goal was to centralize structured data that had previously been duplicated across language editions of Wikipedia (notably in infoboxes), so that a fact stated once could be reused everywhere. Wikidata is widely regarded as the successor to Freebase (knowledge base), the earlier collaborative knowledge base built by Metaweb (launched 2007) and acquired by Google in 2010. After Google announced Freebase's shutdown in December 2014, a partial migration of Freebase content into Wikidata began in 2015, accompanied by a tooling effort known as the Primary Sources Tool. The core unit is the item, identified by a QID — a positive integer prefixed with a capital Q. For example, Douglas Adams is Q42, Earth is Q2, and Wikipedia itself is Q52. Items carry multilingual labels, descriptions, and aliases, and are connected through property identifiers prefixed with P (such as P31 for "instance of" or P569 for "date of birth"). Each statement is a subject-property-value triple that may be qualified, ranked, and referenced to external sources, which makes the dataset compatible with RDF and the broader semantic web. By the mid-2020s the project hosts on the order of 100 million items and well over a billion statements. A public SPARQL endpoint at query.wikidata.org allows arbitrary structured queries, with a built-in query editor, result visualizations, and a 60-second per-query timeout. Bulk data is also available as JSON, RDF, and XML dumps. Downstream consumers include Wikipedia infoboxes (via Lua modules that pull statements directly from Wikidata), Google's Knowledge Graph (which sources some entity facts and identifiers), Apple's Siri and Amazon Alexa for entity lookups, and OpenStreetMap, which cross-references map features to Wikidata QIDs. Researchers in the life sciences, libraries, and digital humanities use it as a stable identifier hub. All content is released under the CC0 Public Domain Dedication, meaning facts can be reused without attribution requirements. The underlying software is MediaWiki with the Wikibase extension, which other organizations also deploy to run their own structured-data wikis.