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Prediction Market Odds API — Polymarket + Kalshi

Search or look up Polymarket and Kalshi prediction markets and get one unified JSON schema back: prices, volume, liquidity, order books, and de-vigged fair probabilities (multiplicative/power method). No API key needed — built for research, arbitrage-scanning, and AI agents.

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Daniel Posztos

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You can access the Prediction Market Odds API — Polymarket + Kalshi programmatically from your own applications by using the Apify API. You can also choose the language preference from below. To use the Apify API, you’ll need an Apify account and your API token, found in Integrations settings in Apify Console.

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          "query": {
            "title": "Search query",
            "type": "string",
            "description": "Keyword(s) to search for across market questions/titles, e.g. \"bitcoin\", \"2028 election\", \"Fed rate cut\". Use this OR 'market_ids' below — you don't need both. Leave empty if you already know the exact market ID(s) you want (use 'market_ids' instead)."
          },
          "market_ids": {
            "title": "Market IDs",
            "type": "array",
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          "platforms": {
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Prediction Market Odds API — Polymarket + Kalshi OpenAPI definition

OpenAPI is a standard for designing and describing RESTful APIs, allowing developers to define API structure, endpoints, and data formats in a machine-readable way. It simplifies API development, integration, and documentation.

OpenAPI is effective when used with AI agents and GPTs by standardizing how these systems interact with various APIs, for reliable integrations and efficient communication.

By defining machine-readable API specifications, OpenAPI allows AI models like GPTs to understand and use varied data sources, improving accuracy. This accelerates development, reduces errors, and provides context-aware responses, making OpenAPI a core component for AI applications.

You can download the OpenAPI definitions for Prediction Market Odds API — Polymarket + Kalshi from the options below:

OpenAPI.json

If you’d like to learn more about how OpenAPI powers GPTs, read our blog post.

You can also check out our other API clients:

Prediction Market Odds API — Polymarket + Kalshi API in Python

Prediction Market Odds API — Polymarket + Kalshi API in JavaScript

Prediction Market Odds API — Polymarket + Kalshi API through CLI

Prediction Market Odds API — Polymarket + Kalshi API

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[💵 $2.00 / 1K] Scrape live prediction markets across Polymarket, Kalshi, and Manifold in one unified schema: odds, implied probability, prices, volume, and liquidity.

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Scrape Polymarket & Kalshi prediction markets: live odds & implied probability, 24h/weekly volume, liquidity, order flow (trades), top holders, wallet P&L, price history, and cross-platform arbitrage. Keyless, no browser. Monitor mode tracks odds moves and new markets. Export to JSON, CSV or Excel.

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Track live Kalshi prediction markets: yes/no bid/ask, last price, implied probability, volume, liquidity, and close time. For traders, researchers, and media tracking event odds.

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Track Polymarket prediction markets: outcomes and outcome prices/odds, volume, liquidity, and end date. For traders, researchers, and media tracking event probabilities.

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Polymarket Scraper

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Scrape prediction market data from Polymarket. Get real-time odds, trading volume, liquidity, and outcomes for any market. Perfect for trading bots, AI agents, data analysis, and research. No API key needed.

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Prediction Market Odds — Kalshi & Polymarket

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Live odds, market catalogs, and historical candles from the two big US prediction markets, via their official APIs. Unified schema, agent/RAG-friendly.

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Polymarket Market Data Scraper

meticulous_sweetwilliam/polymarket-market-data

Extract real-time Polymarket prediction market data: market metadata, prices, volumes, liquidity, and event outcomes. Scrapes the Polymarket API and Gamma Markets API for comprehensive prediction market analytics.

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Polymarket Prediction Market Scraper

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Scrape Polymarket prediction markets — active markets with prices, volumes, liquidity, whale trades ($10K+), and market analytics. No API key required. Outputs JSON, CSV, or Excel.