Kalshi API

Kalshi is the first CFTC-regulated prediction market exchange in the United States, offering event contracts on topics ranging from politics and economics to weather and technology. Codex will index all Kalshi markets, events, trades, and trader activity, providing comprehensive access to market data through a unified GraphQL API.

Prediction Market data is currently in beta and actively being worked on. Both Polymarket and Kalshi data are available now.At least for the time being, these endpoints require a Growth or Enterprise plan. Learn more.

Platform Information

Property	Value
Platform	Kalshi
Protocol Filter	`KALSHI`
Status	Live
Type	Regulated Exchange (CFTC)

Why Use Codex Over the Kalshi API Directly?

	Codex API	Kalshi API
Rate Limits	1,000+ req/s	~20 req/s
Ranking signals	Sort events or markets by trending score, volume, liquidity, open interest, trades, unique traders, or `% change` of any of these at 5m / 1h / 4h / 12h / 24h / 1w	`/events` and `/markets` expose no sort parameter at all. To rank by 24h volume you page through every open event and sort client-side
Time-windowed stats	Volume, trades, unique traders, liquidity, open interest, and `% change` for each at 5m / 1h / 4h / 12h / 24h / 1w	`volume_24h_fp` only. No 5m / 1h / 4h / 12h / 1w windows, no trade counts, no liquidity or OI change
Event-level rollups	Each event response includes aggregated volume, liquidity, OI, trade count, and unique traders across all child markets	Event object is pure metadata. You sum per-market data yourself
Filtering	Filter events and markets on every stat above plus categories, dates, status, protocol	`status`, `series_ticker`, `event_ticker`, `tickers`, and timestamp ranges. No volume, liquidity, or OI filters
Cross-venue	One query, one schema, one ranking system covering Kalshi and Polymarket (plus future venues)	Kalshi only. Integrating Polymarket means a second vendor, second auth, second schema

Understanding Events and Markets

Events are collections of related markets. For example:

Event: “Champions League Final 2026”
- Market 1: “Will Team A win?”
- Market 2: “Will the score be over 2.5 goals?”
- Market 3: “Will there be a penalty?”

Use filterPredictionEvents to find trending high-level topics. Use filterPredictionMarkets to find trending markets.

ID Formats

Kalshi uses specific ID formats to uniquely identify markets, events, and traders across the platform:

Market ID

Format: <marketSlug>:Kalshi Example: KXMVECROSSCATEGORY-S2026A4A05B370DF-F1FBA451AA9:Kalshi

marketSlug: The Kalshi market identifier (venue market slug)
Kalshi: The protocol identifier

Event ID

Format: <eventSlug>:Kalshi Example: KXMVESPORTSMULTIGAMEEXTENDED-S2026350C4EF9BCE:Kalshi

eventSlug: The Kalshi event identifier (venue event slug)
Kalshi: The protocol identifier

Kalshi uses slug-based identifiers rather than blockchain addresses since it operates as a centralized, CFTC-regulated exchange (not on-chain like Polymarket).

Kalshi-Specific Limitations

Trader data is not available for Kalshi. Due to privacy considerations on Kalshi’s regulated exchange, individual trader information is not exposed through their API. This means:

No traderId filtering is available on any endpoints
Trader-specific queries and endpoints cannot be used with Kalshi data
Trade data shows aggregate activity but not individual trader identities
Trade events show TRADE type only (no distinction between BUY/SELL)

Supported APIs

Market & Event API

Filter Prediction Events — Query Kalshi events with advanced filtering
Filter Prediction Markets — Search and filter Kalshi markets by volume, liquidity, category, and other criteria
Get Detailed Event Stats — Fetch detailed statistics for Kalshi events
Get Detailed Market Stats — Retrieve comprehensive trading metrics for any Kalshi market
Get Event Price Bars — Retrieve event-level price history for charting
Get Market Price Bars — Fetch OHLC price data for Kalshi markets

Trading & Activity API

Get Prediction Trades — Query trade history and aggregate trading activity on Kalshi (no individual trader data)

Market Discovery API

Get Prediction Categories — Browse Kalshi categories (Politics, Economics, Weather, etc.)

Example Queries (Available Soon)

{
  filterPredictionEvents(
    filters: {
      protocol: KALSHI
      status: OPEN
    }
    rankings: [{ attribute: trendingScore24h, direction: DESC }]
    limit: 10
  ) {
    count
    results {
      event {
        question
        description
      }
      marketCount
      volumeUsd24h
      trendingScore24h
    }
  }
}

Find Top Kalshi Markets by 24h Volume

{
  filterPredictionMarkets(
    filters: {
      protocol: KALSHI
      status: OPEN
    }
    rankings: [{ attribute: volumeUsd24h, direction: DESC }]
    limit: 10
  ) {
    count
    results {
      id
      eventLabel
      protocol
      market {
        question
        label
        status
        protocol
      }
      volumeUsd24h
      liquidityUsd
      trades24h
      uniqueTraders24h
      outcome0 {
        label
        lastPriceUsd
      }
      outcome1 {
        label
        lastPriceUsd
      }
    }
  }
}

Find Kalshi Markets in Economics Category

{
  filterPredictionMarkets(
    filters: {
      protocol: KALSHI
      status: OPEN
      categories: ["economics"]
    }
    rankings: [{ attribute: volumeUsd24h, direction: DESC }]
    limit: 20
  ) {
    count
    results {
      id
      eventLabel
      market {
        question
      }
      categories
      volumeUsd24h
      liquidityUsd
      outcome0 {
        label
        lastPriceUsd
      }
      outcome1 {
        label
        lastPriceUsd
      }
    }
  }
}

Get Price History for a Market

{
  predictionMarketBars(
    input: {
      marketId: "KXMVECROSSCATEGORY-S2026A4A05B370DF-F1FBA451AA9:Kalshi"
      resolution: hour1
      from: 1772665600
      to: 1773270400
    }
  ) {
    marketId
    bars {
      t
      volumeUsd
      trades
      uniqueTraders
      outcome0 {
        priceUsd {
          o
          h
          l
          c
        }
      }
      outcome1 {
        priceUsd {
          o
          h
          l
          c
        }
      }
    }
  }
}

Try It in the Explorer

Test any Kalshi query directly in the Codex GraphQL Explorer.

Recipes

Step-by-step guides for building with prediction market data:

Discover Prediction Markets

Browse categories, trending events, and filter markets.

Prediction Charts

Outcome probability charts, multi-market comparisons, and OHLC data.

Prediction Event Dashboard

Build a complete event detail page with real-time data.

Supported Prediction Markets Overview — All supported platforms
Polymarket API — Live prediction market data

Overview

EVM Networks

Non-EVM

Launchpads

Prediction Markets

Platform Information

Why Use Codex Over the Kalshi API Directly?

Understanding Events and Markets

ID Formats

Market ID

Event ID

Kalshi-Specific Limitations

Supported APIs

Market & Event API

Trading & Activity API

Market Discovery API

Example Queries (Available Soon)

Find Top Kalshi Markets by 24h Volume

Find Kalshi Markets in Economics Category

Get Price History for a Market

Try It in the Explorer

Recipes

Discover Prediction Markets

Prediction Charts

Prediction Event Dashboard

​Platform Information

​Why Use Codex Over the Kalshi API Directly?

​Understanding Events and Markets

​ID Formats

​Market ID

​Event ID

​Kalshi-Specific Limitations

​Supported APIs

​Market & Event API

​Trading & Activity API

​Market Discovery API

​Example Queries (Available Soon)

​Find Trending Kalshi Events

​Find Top Kalshi Markets by 24h Volume

​Find Kalshi Markets in Economics Category

​Get Price History for a Market

​Try It in the Explorer

​Recipes

Discover Prediction Markets

Prediction Charts

Prediction Event Dashboard

​Related Resources

Platform Information

Why Use Codex Over the Kalshi API Directly?

Understanding Events and Markets

ID Formats

Market ID

Event ID

Kalshi-Specific Limitations

Supported APIs

Market & Event API

Trading & Activity API

Market Discovery API

Example Queries (Available Soon)

Find Trending Kalshi Events

Find Top Kalshi Markets by 24h Volume

Find Kalshi Markets in Economics Category

Get Price History for a Market

Try It in the Explorer

Recipes

Related Resources