Wikidata vs Wikipedia

Wikidata's action API exposes the structured, multilingual knowledge base behind Wikipedia's infoboxes — entity search, full item/property retrieval, and SPARQL-style queries over billions of statements. All read operations (wbsearchentities, wbgetentities, wbgetclaims, and friends) are keyless; OAuth only comes into play for authenticated edits/writes, which this directory entry isn't about. CORS is opt-in per request via the documented `origin=*` query parameter, which returns a wildcard Access-Control-Allow-Origin.

The MediaWiki action API that powers Wikipedia gives keyless access to full-text search, page content/extracts, revision history, and category membership across every language edition. A live probe of en.wikipedia.org/w/api.php confirms open, keyless reads and resolves the CORS story: browsers must append the documented `origin=*` query parameter (a plain Origin header alone is rejected as a "mismatch"), after which the response carries a wildcard Access-Control-Allow-Origin.