wikidata_qid. Wikidata is a free, structured database that stores hundreds of external identifiers for each entity, so the Q-ID is a ready-made join key: from one Oddpool entity you can reach a politician’s campaign-finance record, a company’s stock ticker and LEI, a team’s league and roster, and more, without maintaining your own entity-matching layer.
The pattern is always the same: read wikidata_qid off the entity, then query Wikidata with it.
Wikidata asks every caller to send a descriptive
User-Agent (an app name and contact), and it rate-limits anonymous traffic. The examples below set one. For heavy or repeated use, cache what you pull.Turn a Q-ID into a name and profile
The simplest call: fetch an entity’s labels, description, and claims as JSON, no query language needed.Cross-walk an election market’s candidates to campaign finance
For an election market, take each candidate outcome’sentity.wikidata_qid and resolve them, in one request, to their campaign-finance identifiers. wdt:P2686 is the OpenSecrets people ID and wdt:P2390 is the Ballotpedia ID; from either you can pull filings, totals, and donor data.
Get a company’s ticker, exchange, and LEI
For a market on a public company, resolve the entity to its listings and legal identifiers.p:P414 is the stock-exchange statement, with the ticker as a pq:P249 qualifier, and wdt:P1278 is the Legal Entity Identifier.
Common cross-walks
A few properties useful for prediction-market data. Use the external-ID discovery query above to find the rest.
Wikidata publishes the full list of external-identifier properties and a public SPARQL endpoint.