Polymarket Scraper — Markets, Odds & Price History

Scrape Polymarket prediction markets into clean, structured data: market questions, outcome odds (probability %), prices, best bid/ask, volume (total, 24h, 7 days), liquidity, start and end dates, categories/tags, resolved outcomes and optional price history time series. No login, API key, wallet or browser needed. The Actor uses Polymarket's public Gamma and CLOB APIs.

Monitor mode remembers every market and its odds between runs and outputs only what changed: new markets, odds swings above your threshold (in percentage points) and markets that closed or resolved. Schedule it hourly and get a prediction-market alert feed. You pay only for the changes.

Why this Polymarket scraper

• Six ways to pick markets: top by total volume, trending (24h volume), ending soon, keyword search, tags/categories (politics, crypto, sports, ...) and specific event or market URLs.
• Odds ready to use: Polymarket returns outcomes, prices and token IDs as JSON strings. The Actor parses them into an outcomes array with price (0–1) and probability (%) for each outcome, plus leadingOutcome.
• Price history: add a probability time series per market (last hour up to all time, custom resolution).
• Resolved markets: closed markets include resolvedOutcome (e.g. "Yes", a team name, or "50-50").
• Odds-change monitoring with a free, silent baseline run, a configurable threshold and "compare with previous run" or "compare with last alert" logic.
• Filters: only open markets, minimum volume, minimum liquidity, tags, max items.
• Fast and polite: official public JSON APIs, cursor pagination, retries with backoff and small delays.

Use cases

• Research: study forecasting accuracy, market efficiency, calibration and crowd wisdom with structured data.
• News & media: quote live odds on elections, Fed decisions, geopolitics, sports and crypto; spot big moves for stories.
• Trading models & quant: feed odds, spreads, volume and price history into models, backtests and dashboards.
• AI agents & LLM tools: give agents current probabilities on world events as JSON (works with Apify MCP / API).
• Sentiment dashboards: track what the market thinks about elections, rates, wars or launches in Google Sheets, Looker Studio, Power BI or your database.
• Alerts: get a Slack/email/webhook message when odds on a market you follow swing by 10 points.

Input

Field	Description
mode	topByVolume (default), trending (24h volume), endingSoon, search, byTagSlug, byEventSlugs.
keywords	Search terms for search mode, e.g. bitcoin, fed rates. maxItems is split across keywords.
tags	Tag slugs such as politics, crypto, sports, geopolitics, economy. Required for byTagSlug; in other modes they narrow the results.
eventSlugs	Event URLs (https://polymarket.com/event/<slug>), market URLs or bare slugs for byEventSlugs.
onlyActive	Only open markets (default on). Turn off to include closed/resolved markets.
minVolume	Minimum total volume in USD (default 0).
minLiquidity	Minimum liquidity in USD (default 0).
maxItems	Maximum number of markets (default 100, up to 10,000). In monitor mode: size of the watched list.
includePriceHistory	Add priceHistory (probability % of the first outcome over time). One extra request per market.
priceHistoryInterval	1h, 6h, 1d, 1w (default), 1m, max.
priceHistoryFidelity	Minutes between points; 0 = automatic.
monitorMode	Output only changes since the previous run.
monitorId	Separate saved state per watchlist (default default).
oddsChangeThreshold	Minimum move in percentage points to report an odds change (default 5).
compareTo	lastRun (default) or lastAlert (also catches slow drifts).
baselineOnFirstRun	First run of a watchlist saves odds silently (no output, no cost).
reportNewMarkets, reportOddsChanges, reportResolved	Change types to output (default on).

Example input: trending markets with price history

{
  "mode": "trending",
  "maxItems": 50,
  "minLiquidity": 10000,
  "includePriceHistory": true,
  "priceHistoryInterval": "1d"
}

Example input: keyword search in a category

{
  "mode": "search",
  "keywords": ["bitcoin", "fed rates"],
  "minVolume": 5000,
  "maxItems": 100
}

Example input: specific events

{
  "mode": "byEventSlugs",
  "eventSlugs": [
    "https://polymarket.com/event/will-the-us-invade-iran-before-2027",
    "presidential-election-winner-2024"
  ],
  "onlyActive": false
}

Example input: hourly odds-swing monitor on politics

{
  "mode": "byTagSlug",
  "tags": ["politics", "geopolitics"],
  "maxItems": 300,
  "minVolume": 100000,
  "monitorMode": true,
  "monitorId": "politics-swings",
  "oddsChangeThreshold": 5
}

Output

One row per market. Real example from a test run (mode: "trending", price history 1d at 240-minute resolution):

{
  "marketId": "5184010",
  "question": "Will Manchester City FC win on 2026-10-14?",
  "slug": "ucl-mnc-psg-2026-10-14-mnc",
  "url": "https://polymarket.com/event/ucl-mnc-psg-2026-10-14",
  "eventId": "1114982",
  "eventTitle": "Manchester City FC vs. Paris Saint-Germain FC",
  "eventSlug": "ucl-mnc-psg-2026-10-14",
  "groupItemTitle": "Manchester City FC",
  "category": "Sports",
  "tags": ["Sports", "Games", "Soccer", "UCL", "UCL Matchday"],
  "outcomes": [
    { "name": "Yes", "price": 0.475, "probability": 47.5, "tokenId": "30251429612449430455264370878544256883870033672058898853863549939939326972421" },
    { "name": "No", "price": 0.525, "probability": 52.5, "tokenId": "78954184754912276237571294773010091711341505525591694748702579984199183887817" }
  ],
  "leadingOutcome": "No",
  "leadingProbability": 52.5,
  "volume": 875707.65,
  "volume24h": 857624.68,
  "volume1wk": 873415.78,
  "volume1mo": 875707.65,
  "liquidity": 612908.42,
  "lastTradePrice": 0.48,
  "bestBid": 0.47,
  "bestAsk": 0.48,
  "spread": 0.01,
  "oneDayPriceChange": 0.03,
  "oneWeekPriceChange": 0.06,
  "startDate": "2026-10-01T18:00:15.000Z",
  "endDate": "2026-10-14T19:00:00.000Z",
  "createdAt": "2026-10-01T18:00:05.703Z",
  "closedTime": null,
  "active": true,
  "closed": false,
  "acceptingOrders": true,
  "resolved": false,
  "resolvedOutcome": null,
  "negRisk": true,
  "conditionId": "0xf8f3e450b7c01e9d8876f831eeb8955690af9a62121f9341ff30ebb60cc996f5",
  "resolutionSource": "https://www.uefa.com/",
  "image": "https://polymarket-upload.s3.us-east-2.amazonaws.com/champions-league-pic-QIUFsL8vaDdq.png",
  "scrapedAt": "2026-10-14T09:53:08.926Z",
  "priceHistoryOutcome": "Yes",
  "priceHistory": [
    { "t": "2026-10-13T12:00:38.000Z", "p": 44.5 },
    { "t": "2026-10-13T16:00:26.000Z", "p": 44.5 },
    { "t": "2026-10-13T20:00:27.000Z", "p": 44.5 },
    { "t": "2026-10-14T00:00:39.000Z", "p": 44.5 },
    { "t": "2026-10-14T04:00:27.000Z", "p": 45.5 },
    { "t": "2026-10-14T08:00:27.000Z", "p": 46.5 },
    { "t": "2026-10-14T09:52:23.000Z", "p": 47.5 }
  ]
}

Units: outcomes[].probability, leadingProbability and priceHistory[].p are percent (0–100). outcomes[].price, lastTradePrice, bestBid, bestAsk, spread, oneDayPriceChange and oneWeekPriceChange are in Polymarket price units (0–1 USDC per share, so 0.03 = +3 percentage points). Volumes and liquidity are in USD. In search mode each row also has searchKeyword.

Closed markets (with onlyActive: false) have closed: true, closedTime, resolved and resolvedOutcome (the winning outcome, or "50-50").

In monitor mode each row also has:

{
  "changeType": "oddsChange",
  "changes": ["oddsChange"],
  "previousOutcomes": [{ "name": "Yes", "probability": 71.5 }, { "name": "No", "probability": 28.5 }],
  "probabilityChangePp": 10,
  "maxProbabilityChangePp": 10,
  "previousCheckedAt": "2026-10-14T09:51:59.307Z",
  "firstSeenAt": "2026-10-14T09:51:48.380Z"
}

changeType is one of new, oddsChange, resolved. probabilityChangePp is the signed move of the first outcome (e.g. "Yes"), maxProbabilityChangePp the largest move of any outcome.

A run report (inputs, tags resolved, events found, markets matched, errors, monitor counts) is saved to the SUMMARY record of the run's key-value store. Invalid slugs or tags are listed there with an error and the run continues.

How monitoring works

• The state is saved in the named key-value store polymarket-monitor under state-<monitorId> (gzipped JSON).
• The first run of a watchlist (mode + tags + keywords + events) only saves the odds (if baselineOnFirstRun is on).
• New = a market this monitor has never seen. With topByVolume/trending, a market that enters your top-N list for the first time counts as new.
• Odds change = any outcome moved by at least oddsChangeThreshold percentage points since the previous run (compareTo: "lastRun") or since it was last reported ("lastAlert").
• Resolved = a watched market closed. Markets that drop out of your list are checked by ID, so you are told when they resolve even with onlyActive on.
• If the run's cost limit is reached, unreported changes stay pending for the next run. Markets not seen for 30 days are forgotten.

Pricing

Pay per market: you pay a small fee for each market row in the dataset (event market). 100 trending markets cost 100 results. In monitor mode you pay only for reported changes, so an hourly watch on hundreds of markets usually costs cents per day. Price history is included in the same per-market price. Set a maximum cost per run and the Actor stops cleanly when it is reached.

FAQ

Do I need a Polymarket account, API key or crypto wallet? No. The Actor reads Polymarket's public market data APIs, the same data the website shows to every visitor.

How fresh are the odds? They are live at run time. outcomes[].price is Polymarket's displayed price (midpoint or last trade), and bestBid/bestAsk show the order book. Schedule the Actor (every 5–60 minutes) for near-real-time tracking.

How do I find a tag slug? Open a category on polymarket.com; the last part of the URL is the slug (/predictions/crypto → crypto). Common ones: politics, crypto, sports, geopolitics, economy, tech, culture, elections.

Why does an event return several markets? Polymarket events with several possible answers (e.g. "Fed decision in October") are made of one Yes/No market per answer. Each one is a row; eventTitle and groupItemTitle tell them apart. Use a market URL to get just one.

Can I get historical prices for resolved markets? Yes. Use onlyActive: false, includePriceHistory: true and priceHistoryInterval: "max".

Can I export to Excel, CSV or Google Sheets? Yes. Apify datasets download as JSON, CSV, Excel, XML or HTML, and integrate with Google Sheets, Zapier, Make, Slack and webhooks.

Limitations

• Price history covers the first outcome of each market (e.g. "Yes"); for Yes/No markets the other side is 100 − p.
• Keyword search uses Polymarket's own search ranking; results per keyword are capped at 20 result pages.
• Markets restricted in some regions are still listed (the data is public), but trading rules are up to Polymarket.
• Volumes and liquidity are as reported by Polymarket's API and may differ slightly from the website's rounding.

Disclaimer

This Actor provides data only. Nothing here is financial, investment or betting advice. Prediction market prices reflect traders' bets, not certainties, and can be wrong, illiquid or manipulated. Do your own research.

Legal

The Actor reads only public market data that Polymarket publishes through its public APIs. It does not log in, trade, bypass protections or collect personal data. Market texts and images remain the property of their owners. Make sure your use of the data and any trading complies with Polymarket's terms and the laws of your jurisdiction.

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