Prediction Market Movers | Polymarket & Kalshi Catalyst Feed

Find the markets where something is happening — before everyone else does. One run scans the top markets on both Polymarket and Kalshi and returns a single ranked feed of the biggest catalysts: 24-hour odds swings, volume spikes, fast 1-hour movers and markets closing within 48 hours — each with a 0-100 catalyst score.

No API keys, no wallet, no proxies. Pure fast HTTP against both platforms' public APIs.

Who is this for?

• Prediction market traders — a daily (or hourly) shortlist of where the action is: what moved 10+ points, what's spiking in volume, what resolves tonight.
• News desks & newsletter writers — "what do markets suddenly believe?" ranked and structured. Big odds swings are the story.
• Quants & AI agents — a clean cross-platform catalyst signal to trigger deeper analysis, alerts or research pipelines.
• Kalshi ↔ Polymarket arbitrageurs — movers create temporary mispricings; catch them as they form.

What you get (per row)

Field	Description
rank, catalystScore	Position in the ranked feed + 0-100 combined activity score
signals	BIG_SWING, VOLUME_SPIKE, CLOSING_SOON, FAST_MOVER_1H, LIVE_EVENT
platform, marketId, title, category, url	Which market, on which platform, with direct link
yesPrice, impliedProbabilityPct	Current Yes price / implied probability
priceChange24h, priceChange1h	Odds movement over 24h and 1h (1h: Polymarket)
volume24hUsd, volumeTotalUsd, liquidityUsd, openInterest	Money flowing through the market
spread, bestBid, bestAsk	Execution quality right now
closeTime, hoursToClose	When it resolves
scrapedAt	Snapshot timestamp

Catalyst score = 45% odds swing (24h) + 35% dollar volume (24h) + 10% closing-within-48h + 10% 1-hour momentum. Sort by raw price move or raw volume instead if you prefer.

Pricing — pay only for the shortlist

Pay-per-event: $0.0096 per mover row ($9.60 per 1,000) + $0.001 per run start. Scanning hundreds of markets is free — you pay only for the ranked rows that pass your filters (default: top 100). Junk zero-volume markets, filtered-out markets and failed fetches are never charged. A default daily run costs about $0.97.

Example input

{
  "platforms": ["polymarket", "kalshi"],
  "minVolume24hUsd": 5000,
  "minAbsPriceChange24h": "0.05",
  "maxRows": 50,
  "sortBy": "catalystScore"
}

→ "the 50 biggest catalysts across both platforms, at least a 5-point swing, at least $5k traded today."

Schedule it (recommended)

Catalysts die fast. Click Schedule in Apify Console — @hourly during market hours or @daily for a morning briefing. Wire the dataset to Slack/Discord/email via Integrations, or export JSON/CSV.

Use with AI agents & MCP

Works out of the box with the Apify MCP server: let your agent ask "which prediction markets moved the most today and why might that be?" — the signals array and stable schema are built for automated reasoning. API: https://api.apify.com/v2/acts/tactful_anvil~prediction-market-movers/runs.

Related Actors

• Polymarket Top Traders Scraper — Whale Positions & Copy Feed — see what the most profitable whales hold in the markets that are moving.
• Polymarket + Kalshi Arbitrage Scanner — fee-adjusted risk-free spreads between the two platforms.
• Kalshi Weather Markets Scraper — every Kalshi weather market with live odds.

Legal & fair use

Reads only public, unauthenticated JSON APIs (Polymarket Gamma API, Kalshi trade API v2) with polite pacing. Market data, not financial advice — verify prices on-platform before trading.

Changelog

• 0.1.2 (17 Sep 2026) — Fix: Kalshi's API now reports liquidity_dollars = 0 for every market, which had silently zeroed liquidityUsd on the whole Kalshi leg. Kalshi rows now fall back to top-of-book resting collateral (bid size × price + ask size × (1 − price)) computed from the same payload — no extra requests, no price change. Polymarket rows unchanged.
• 0.1.1 (5 Sep 2026) — Fix: Kalshi listing is now flooded with zero-volume multivariate (parlay) shards; the Actor filters them out (mve_filter=exclude) so the Kalshi leg is back to ~50% of the feed instead of silently returning 0 rows.
• 0.1.0 (1 Sep 2026) — Launch: Polymarket + Kalshi movers in one ranked feed with 0–100 catalyst score and signals.

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