BallotData.aiAPI
Get an API key

Endorsement data for researchers

The only source of AI‑optimized endorsement and election data

The BallotData API gives researchers, and the AI tools they use, every endorsement we collect across the country: who endorsed whom, in which contest, tied to the choice on the printed ballot and to the page it came from. Structured so assistants and agents read it right.

  • An MCP server for Claude, ChatGPT and other AI assistants
  • The same fields in every state, with a source for every endorsement
  • An OpenAPI 3.1 spec that describes every parameter, plus Python and JavaScript libraries
  • Parties, unions, newspapers, advocacy groups and officials, by category
  • One payment, licensed through December 31, 2027

Get an API keyRead the API docs

GET /v1/endorsements/90211example
{
  "id": 90211,
  "endorser": {
    "name": "San Francisco Labor Council",
    "category": { "slug": "labor", "name": "Labor" }
  },
  "contest": {
    "title": "Member, Board of Supervisors, District 8",
    "vote_method": "ranked_choice"
  },
  "choice": { "label": "Jane Doe" },
  "rank": 1,
  "source_url": "https://sflaborcouncil.org/endorsements",
  "published_on": "2026-09-18"
}

What’s in the API

Endorsements, nationwide

Every endorsement we have, from parties, unions, newspapers, advocacy groups and officials, with its source link and the date it was published. Filter by state, election, contest, endorser or kind of endorser.

  • GET /v1/endorsements
  • GET /v1/endorsers
  • GET /v1/endorser-categories

The ballots they’re on

Every contest with its choices in ballot order and its voting rules (vote for one, vote for several, ranked choice, measures), so each endorsement lines up with the printed ballot.

  • GET /v1/elections
  • GET /v1/contests

Where candidates stand

Candidates’ positions on common issues, from abortion and guns to schools, the safety net and tariffs, as they stated them or as their votes in Congress show, with a link for every one.

  • GET /v1/issue-positions
  • GET /v1/issues

API pricing

One payment licenses the data through December 31, 2027, including every endorsement we add until then. Every data endpoint for the states you buy.

$499One state
$4,999Every state we cover

Get an API keyPython and JavaScript libraries

Returning for 2028

Endorsement Stream

New endorsements sent to you as we find them: over a live stream, as signed postbacks, by email, or as CSV and JSON files. It returns for the 2028 elections and isn’t sold until then.

Get updates when it’s backRead the Stream docs

BallotData API