Prediction Markets API: Polymarket, Kalshi & Manifold Odds

A prediction market odds API for Polymarket, Kalshi and Manifold in one table. Search any topic (an election, the Fed, bitcoin, a sports final) and get every matching market with its implied probability, bid/ask, 24-hour change, volume, liquidity, close date and link, normalized to the same fields across all three platforms. Or leave the search empty to get each platform's top markets. You only pay for markets you get.

💲 Price	$1.50 per 1,000 markets on Apify's Free plan, down to $0.60 on paid plans. Searches that find nothing are free.
⚡ Speed	One search on all 3 platforms in about 5–10 seconds; 4 searches (about 200 markets) in about 30 seconds
📥 Input	Search terms (optional), platforms, sort order, limit, minimum volume
📤 Output	One row per market: probability, all outcomes, last price, bid/ask, 24h change, volume, liquidity, open interest, close date, tags, link
🔌 Sources	Official public APIs of Polymarket (Gamma), Kalshi (trade API v2) and Manifold (v0). No API key, no login, no proxy.

What people use it for

• Compare odds across platforms: the same question on Polymarket, Kalshi and Manifold side by side (e.g. "senate", "fed rate"), to spot disagreements
• News and research: "the market gives X a 33% chance" with a link, for articles, newsletters and dashboards
• Trading signals and alerts: schedule a run every hour and watch change24h and volume24h for sudden moves
• AI agents: give an assistant a live read on what markets expect, with sources (url)
• Datasets: collect closed and resolved markets (includeClosed) to study how well markets predicted outcomes

How to use it

1. Add search terms, one per line (or leave empty for the top markets).
2. Pick platforms, a sort order (24-hour volume, total volume, liquidity or closing soonest) and how many markets per search.
3. Click Start, then download the results as JSON, CSV or Excel, or fetch them through the API.

For AI agents and automations

• One job: live prediction-market odds for a topic. Minimal input: { "searchTerms": ["fed rate"] }
• Fast enough for a single tool call: one search on all 3 platforms finishes in about 5–10 seconds, inside the Apify MCP server's default 30-second wait.
• Where the results are: dataset items (fields below). A run summary is in the key-value store record OUTPUT: status (SUCCEEDED, PARTIAL, STOPPED_AT_SPEND_LIMIT, ABORTED, NO_RESULTS, SOURCE_UNAVAILABLE), results, errorsByCode and a plain-English message.
• Predictable billing: pay per market returned; rows explaining an empty search are free.
• Respects "Max cost per run": it stops cleanly at your limit with status STOPPED_AT_SPEND_LIMIT, keeping everything fetched so far.
• Graceful on abort and restarts: partial results are kept, and a platform restart resumes without duplicates or double charges.
• Honest failures: if the platforms don't answer, the run fails with a clear message and you pay $0.
• Works with the Apify MCP server (Claude, Cursor, other agents), agentic payments, and the API.

Input examples

Fed rate odds on all three platforms, busiest first:

{ "searchTerms": ["fed rate"] }

Top 100 Polymarket markets by 24-hour volume:

{ "platforms": ["polymarket"], "maxMarketsPerSearch": 100 }

Election markets with real money only, at least $100k traded, closing soonest first:

{ "searchTerms": ["election"], "platforms": ["polymarket", "kalshi"], "minVolume": 100000, "sortBy": "closingSoon" }

Output

A real row from a test run (2026-10-29):

{
  "status": "ok",
  "search": "election",
  "rank": 2,
  "platform": "kalshi",
  "marketId": "SENATETX-26-R",
  "question": "Will Republicans win the Senate race in Texas?",
  "eventTitle": "Texas Senate winner?",
  "outcomeLabel": "Ken Paxton",
  "probability": 0.33,
  "outcomes": [
    {
      "name": "Yes",
      "probability": 0.33
    },
    {
      "name": "No",
      "probability": 0.67
    }
  ],
  "lastPrice": 0.33,
  "bestBid": 0.32,
  "bestAsk": 0.33,
  "change24h": -0.02,
  "volume": 32926844.9,
  "volume24h": 2100346.52,
  "volumeUnit": "contracts",
  "liquidity": null,
  "openInterest": 25141953.39,
  "closeTime": "2027-11-03T15:00:00.000Z",
  "isOpen": true,
  "category": [
    "Elections"
  ],
  "url": "https://kalshi.com/markets/senatetx",
  "scrapedAt": "2026-10-29T02:07:07.154Z"
}

Field	Meaning
probability	Implied probability of Yes, 0–1: last traded price (Kalshi: bid/ask midpoint when nothing has traded). Empty for multi-answer Manifold markets; see outcomes.
outcomes	Every outcome with its probability. Multi-answer Manifold markets list each answer.
eventTitle / outcomeLabel	For questions split into one market per outcome (candidates, price levels): the parent question and this market's outcome
change24h	Change in the Yes price over 24 hours (Polymarket and Kalshi)
volume, volume24h, volumeUnit	USD on Polymarket, contracts on Kalshi (each pays $1 if right), mana on Manifold (play money)
liquidity, openInterest	As each platform reports them (Kalshi gives open interest, not liquidity)
closeTime, isOpen	When trading closes, and whether the market is still open
category, url	Platform tags or category, and the link to the market
search, rank	Which search matched, and the position after sorting

Cost examples

Job	Markets	Cost (Free plan)
One topic on 3 platforms, 50 each	150	$0.23
Top 100 markets on each platform	300	$0.45
Hourly check of 5 topics × 20 markets for a month	~72,000	$108 ($43 on Gold)

Set Max cost per run to cap any run, and the actor stops cleanly at the limit.

Integrations

• API: client.actor("t3data/prediction-markets").call({ searchTerms: ["fed rate"] }) (JS), or client.actor("t3data/prediction-markets").call(run_input={"searchTerms": ["fed rate"]}) (Python). Full snippets are on the API tab.
• AI agents (MCP): available as a tool through the Apify MCP server.
• Scheduling: run it hourly or daily with Apify Schedules to track odds over time.
• No-code: Make, Zapier, n8n, Google Sheets, Slack and webhooks, through Apify integrations.
• Export: JSON, CSV, Excel, XML, HTML or RSS.

Error codes (never charged)

Code	Meaning
NO_MARKETS	No market on that platform matches every word of the search
BLOCKED	The platform kept rate-limiting or erroring after retries
NETWORK_ERROR / PARSE_ERROR	The platform didn't answer, or answered with something unexpected

FAQ

How does search work? Every word of your search must appear in the market's question, its parent event or its tags (case doesn't matter). fed rate finds "Fed rate hike in 2026?" and "Fed Decision in December?" markets about interest rates. Kalshi has no search API, so the actor reads all of Kalshi's open markets and filters them the same way.

Why are Kalshi's auto-generated combo markets missing? Kalshi lists thousands of multi-leg parlays (tickers starting KXMVE). They aren't questions anyone searches for, so they're skipped.

Is Manifold real money? No. Manifold uses play money (mana), so its volumes aren't comparable to Polymarket's dollars. Its odds are still a useful third opinion.

Do I need an API key, a wallet or a proxy? No. All three APIs are public and read-only.

Something broke? Open an issue on the Issues tab with your input. Fixes usually ship within a day.

Found it useful? A star rating on this page helps other people find it.

Limits

• Odds are what each platform reports at run time and move constantly. Schedule runs to track them.
• Polymarket search goes up to about 500 events per term; Kalshi is read up to about 12,000 events per run.
• Polymarket is not available to US users and Kalshi is US-regulated; this actor only reads public data and places no trades.

More from T3 Data

• Google Trends API: search interest over time, by region, related queries, trending now
• Google News Scraper: articles with real publisher URLs and optional full text
• YouTube Transcripts, Google Ads Transparency, Google Hotels

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This Actor is an independent tool. It is not affiliated with, endorsed by, or sponsored by Polymarket, Kalshi or Manifold. It only reads their public APIs and places no trades. Nothing here is financial advice.