Polymarket On-chain event markets

Kalshi Regulated prediction contracts

Prediction Markets API
unified events and market data

Query events, markets, prices, orderbooks, OHLC history, and wallet portfolios across Polymarket and Kalshi.

Quick start

GET https://api.tatum.io/v4/data/prediction/markets?limit=20
Header x-api-key: •••••••• Query platform=polymarket&status=active&sort=volume_desc

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What the Prediction Markets API gives you

A single REST surface for browsing and analyzing Polymarket and Kalshi, including events, markets, live prices, orderbooks, history, discovery search, and Polymarket wallet analytics.

Cross-platform hierarchy

List and filter events and markets from both platforms in one response. Pin platform= when you need strict Polymarket-only filters.

Market microstructure

Per-market price, orderbook depth, OHLC candles, recent trades, and top holders, keyed by Polymarket condition IDs or Kalshi tickers.

Wallet & leaderboard intel

Polymarket portfolio summaries, positions, closed history, activity feeds, and volume-ranked top traders, without wiring multiple upstream APIs yourself.

Quick start

One call, both platforms

All routes live under /v4/data/prediction — your Tatum API key only, no Polymarket or Kalshi credentials. List events from both platforms in one feed.

Request

curl --request GET \
  --url 'https://api.tatum.io/v4/data/prediction/events?sort=volume_desc&limit=5' \
  --header 'x-api-key: YOUR_API_KEY'

Response

{
  "data": [
    {
      "id": "12345",
      "platform": "polymarket",
      "title": "2028 US Presidential Election",
      "marketCount": 12,
      "totalVolume": 4823100.5,
      "volumeUnit": "usd",
      "status": "active"
    },
    {
      "id": "KXELONMARS",
      "platform": "kalshi",
      "title": "Will humans land on Mars by 2030?",
      "marketCount": 3,
      "totalVolume": 1542300,
      "volumeUnit": "contracts"
    }
  ],
  "pagination": {
    "cursor": "eyJwbUV2dEN1cnNvciI6…",
    "pageSize": 5
  }
}  // …more fields in the full schema

Core endpoints at a glance

Explore cross-platform GET routes under /v4/data/prediction.

Events cross-platform

List events GET

/v4/data/prediction/events

Merged Polymarket + Kalshi events with volume, liquidity, tags, and cursor pagination. Optional includeMarkets=true.

platform · status · sort · search

Get event by ID GET

/v4/data/prediction/events/{eventId}

Single event with aggregate stats. PM integer IDs or Kalshi tickers — auto-routed by shape.

includeMarkets

Markets cross-platform

List markets GET

/v4/data/prediction/markets

Active and settled markets with outcomes, volume, liquidity, and source URLs. Filter by event, category, tag, or min volume.

eventId · minVolume · endingBefore

Get market by ID GET

/v4/data/prediction/markets/{marketId}

0x-hex condition ID (Polymarket) or uppercase ticker (Kalshi). Includes chain metadata on PM markets.

YES/NO outcomes

Market data per marketId

Price snapshot GET

/v4/data/prediction/markets/{id}/price

Yes/no prices with bid, ask, and sizes. Kalshi includes contract volume units where applicable.

Orderbook GET

/v4/data/prediction/markets/{id}/orderbook

Depth-ranked bids and asks for side=yes|no with optional depth limit.

Price history (OHLC) GET

/v4/data/prediction/markets/{id}/history

Candles from 1m to 1w. Optional source=midpoint on Polymarket for longer ranges.

interval · start · end

Recent trades GET

/v4/data/prediction/markets/{id}/trades

Native fill feed with cursor pagination. Kalshi supports after / before time windows.

Market positions (holders) GET

/v4/data/prediction/markets/{id}/positions

Top wallets by outcome token. Polymarket-only — mirrors upstream market-positions schema.

Polymarket only

Discovery Polymarket

Unified search GET

/v4/data/prediction/search

Events, markets, tags, and profiles in one Gamma /public-search pass-through. Required q parameter.

searchTags · searchProfiles · page

Legacy /tags and /categories routes return 404 — use search instead.

For wallet routes, top traders, and complete request/response schemas, see the Wallet & leaderboard docs →

Detailed docs and MCP server access

Use the API reference for request schemas, platform filter rules, and error codes — or connect the Tatum docs MCP server to query endpoint details in AI workflows.

Open API reference Learn more

Live prediction markets explorer

Add your API key and pull live markets from GET /v4/data/prediction/markets — filter by platform, status, and sort by volume.

Tatum API key Platform Status Sort Limit

Preview locked — sample rows shown until you fetch with your key. Endpoint: /v4/data/prediction/markets

#	Market	Platform	Status	Yes	Volume	Liquidity
1	Will BTC reach $150k in 2026? 0xe06a…c61	polymarket	active	0.42	1.2M	84k
2	Fed cuts rates before July? KXRATEJUL-26	kalshi	open	0.61	420k	—

Explorer locked

Get your API key and click Unlock & fetch to load live Polymarket and Kalshi markets.

Prediction Markets API unified events and market data