Wikidata

Overview

Wikidata is Wikipedia’s structured knowledge base — entities with typed properties (e.g. “Douglas Adams: occupation → writer, birth date → 1952-03-11”), queryable via the MediaWiki API or SPARQL. Anonymous reads are keyless and free (verified live); OAuth is only for edits and user-scoped actions.

Quick Start

Entity search (verified live):

curl "https://www.wikidata.org/w/api.php?action=wbsearchentities&search=dog&language=en&format=json"

Fetch an entity’s data by Q-id:

curl "https://www.wikidata.org/wiki/Special:EntityData/Q42.json"

SPARQL query (Wikidata Query Service):

curl -G "https://query.wikidata.org/sparql" \
  --data-urlencode "query=SELECT ?item ?itemLabel WHERE { ?item wdt:P31 wd:Q146 . SERVICE wikibase:label { bd:serviceParam wikibase:language \"en\" } }" \
  -H "Accept: application/json"

Authentication

• Anonymous: reads are keyless (verified) — search, entity data, SPARQL.
• OAuth: required for edits (creating/updating entities) — the listing’s OAuth flag refers to this.

Rate Limits & Notes

• Read limits are generous; SPARQL queries have a 60-second timeout (use aggregates wisely).
• Entities use stable Q-ids (Q42 = Douglas Adams); properties use P-ids (P31 = instance of).
• Special:EntityData/{Qid}.json is the simplest JSON access — no API params needed.
• The Query Service (SPARQL) is the powerful path for data mining; results in JSON/CSV/TSV.

FAQ

Is Wikidata free? Yes — anonymous reads are free and keyless.

Do I need OAuth? Only for editing — read/search/SPARQL work anonymously.

What’s a Q-id? The stable identifier for an entity (e.g. Q42 = Douglas Adams).