Kalshi & Polymarket Scraper — Odds, Probability, Volume

Live prediction-market odds from Kalshi and Polymarket in one table: implied probability, yes price, bid / ask, spread, 24h move, volume, liquidity, open interest, close time and resolution rules. Search any topic — elections, the Fed, crypto, sports, AI — or get the biggest markets by volume. $1 per 1,000 markets. No login, no API key.

What does this Kalshi and Polymarket scraper do?

For each topic you type (for example fed rate), it searches both exchanges, collects every open market that matches and returns one row per market with the same fields on both venues — so you can compare what Kalshi and Polymarket think about the same event. Leave the topic empty to get the most-traded markets right now.

It uses the exchanges' own public market-data APIs, so it is fast (about 4 seconds for 40 markets in our test) and does not break when the websites change their design.

Why use it

1. Both big exchanges, one schema. platform tells you where each row comes from.
2. Probabilities ready to use. impliedProbabilityPct (0–100), yesPrice, bestBid, bestAsk, spread and change24h — no cents-vs-dollars conversion.
3. Real search on Kalshi too. Topic search on both venues, not only on Polymarket.
4. Filters that matter. Category, minimum volume, sort by 24h volume, total volume, liquidity or closing date.
5. Cheap and simple. $0.001 per market row, no start fee, up to 20 free rows per run (at most half of the run).
6. Built for automation and AI agents. JSON / CSV / Excel, API, schedules, n8n, Make, Zapier and MCP.

How to use it in 3 steps

1. Click Try for free — fed rate and bitcoin are prefilled.
2. Add your topics, pick the exchanges, and optionally a category or minimum volume.
3. Click Start and download the table, or schedule it every hour to track the odds.

Input

Field	What it does
searchTerms	Topics to search (up to 20). Empty = biggest markets by volume.
platforms	kalshi, polymarket or both (default).
maxMarkets	Per topic, 1 to 1,000. Default 100.
category	Optional: Economics, Politics, Elections, Crypto, Sports...
minVolume	Optional minimum total traded volume.
sortBy	volume24h (default), volume, liquidity, closing.
maxTotalChargeUsd	Optional hard cost cap for the run.

{
  "searchTerms": ["fed rate", "recession", "bitcoin"],
  "platforms": ["kalshi", "polymarket"],
  "minVolume": 10000,
  "sortBy": "volume24h",
  "maxMarkets": 50
}

Output

Real example (Kalshi, rules trimmed):

{
  "platform": "kalshi",
  "marketId": "KXFEDDECISION-26OCT-H0",
  "question": "Will the Federal Reserve Hike rates by 0bps at their October 2026 meeting?",
  "eventTitle": "Fed decision in Oct 2026?",
  "outcome": "Fed maintains rate",
  "yesPrice": 0.54,
  "impliedProbabilityPct": 54.0,
  "bestBid": 0.53,
  "bestAsk": 0.55,
  "spread": 0.02,
  "lastPrice": 0.55,
  "change24h": 0.25,
  "volume": 1815793.85,
  "volume24h": 448507.67,
  "openInterest": 839330.16,
  "category": "Economics",
  "closeTime": "2026-10-28T17:59:00Z",
  "marketStatus": "active",
  "rules": "If the Federal Reserve does a Hike of 0bps on October 28, 2026, then the market resolves to Yes...",
  "url": "https://kalshi.com/markets/kxfeddecision",
  "searchQuery": "fed rate",
  "status": "ok"
}

Polymarket rows have the same fields, plus outcomes (every outcome with its price) for multi-outcome markets. openInterest is Kalshi-only.

How much does it cost?

Event	Price
Market row	$0.001 ($1 per 1,000)
Start fee	none

Example: a daily snapshot of 200 markets for a month = 6,000 rows = $6. Up to 20 rows of every run are free (at most half of the run). Paid Apify plans get lower tier prices.

Use cases

• Traders and analysts — compare Kalshi vs Polymarket odds on the same event.
• News and research — "what do markets say?" for elections, Fed decisions, recession, AI milestones, with a probability history you build by scheduling runs.
• Dashboards and alerts — send big 24h moves to Slack or Google Sheets.
• AI agents — let an assistant check live market probabilities before answering.

Use it from code (API)

Python

from apify_client import ApifyClient

client = ApifyClient("<YOUR_APIFY_TOKEN>")
run = client.actor("om_kh/kalshi-polymarket-scraper").call(run_input={
    "searchTerms": ["fed rate"],
    "minVolume": 10000,
})
for m in client.dataset(run["defaultDatasetId"]).iterate_items():
    print(m["platform"], m["question"], m["impliedProbabilityPct"], m["change24h"])

cURL

curl -X POST "https://api.apify.com/v2/acts/om_kh~kalshi-polymarket-scraper/run-sync-get-dataset-items?token=<YOUR_APIFY_TOKEN>" \
  -H "Content-Type: application/json" \
  -d '{"searchTerms": ["election"], "maxMarkets": 50}'

Integrations: n8n, Make, Zapier, Google Sheets

Schedule the Actor (every hour or every day) and push rows to Google Sheets, Airtable or a Slack channel with the Apify app in n8n, Make or Zapier to keep a probability history.

Use it from an AI agent (MCP)

Connect Claude, Cursor or any MCP client to https://mcp.apify.com and add om_kh/kalshi-polymarket-scraper as a tool: "what is the market probability of a Fed cut in October on Kalshi and Polymarket?".

Tips and limits

• Prices are between 0 and 1; impliedProbabilityPct = price × 100. On Kalshi it is the mid of bid and ask (last trade when there is no ask).
• Kalshi volume is counted in contracts, Polymarket volume in USD.
• Market data is informational only. This Actor does not place trades and is not financial advice.

FAQ

Do I need a Kalshi or Polymarket account? No. Both exchanges publish market data publicly.

How often is the data updated? Every run reads live data. Schedule the Actor as often as you need.

Can I get only one exchange? Yes, set platforms to ["kalshi"] or ["polymarket"].

Is it legal? It reads public market data that the exchanges publish through their own APIs.

Related Actors

• Google Trends Scraper - Interest, Regions, Rising Queries — is public interest in the topic growing?
• Google News API - Headlines, Source, Date, No Login — the news moving the odds.
• X (Twitter) Search Scraper - Posts, Likes, Replies — what people say about the event.