Polymarket Scanner API

Real-time arbitrage and mispricing detection across 10,000+ prediction markets on Polymarket.

What It Detects

• Exclusive outcome mispricings — When yes prices don't sum to 1.0
• Ladder contradictions — When higher thresholds are priced above lower ones
• Cross-market conflicts — Contradictions between related markets

Quick Start

# Try the hosted API (free, 3 requests/day)
curl https://polymarket-scanner-api.onrender.com/api/scan

# Filter by minimum profit and liquidity
curl "https://polymarket-scanner-api.onrender.com/api/scan?min_profit=5&min_liquidity=1000"

Self-Host

git clone https://github.com/vesper-astrena/polymarket-scanner-api.git
cd polymarket-scanner-api
pip install -r requirements.txt
python main.py
# → http://localhost:8000

API Reference

GET /api/scan

Returns current arbitrage opportunities.

Parameter	Type	Default	Description
min_profit	float	0	Minimum estimated profit %
min_liquidity	float	0	Minimum liquidity in USD
limit	int	50	Max opportunities to return

Response:

{
  "scan_time": "2026-03-12T00:22:58Z",
  "events_scanned": 750,
  "markets_scanned": 11330,
  "opportunities_found": 110,
  "opportunities": [
    {
      "type": "exclusive_mispricing",
      "description": "Counter-Strike: Team Nemesis vs ARCRED",
      "deviation_pct": 473.8,
      "estimated_profit_pct": 145.25,
      "min_liquidity_usd": 451.0,
      "strategy": "BUY_ALL_NO",
      "confidence": "high"
    }
  ]
}

GET /api/health

Health check endpoint.

Pricing

	Free	Pro ($29/mo)
API calls	3/day	Unlimited
Opportunities	Top 10	All (50+)
Cache	5 min	Real-time
Webhooks	—	Coming soon

Get Pro Access →

How It Works

The scanner fetches all active events from Polymarket's public Gamma API, parses market data, and runs three detection algorithms:

1. Exclusive outcomes: Checks if yes prices for mutually exclusive outcomes sum to 1.0
2. Ladder contradictions: Verifies that higher thresholds have lower probabilities
3. Cross-market: Finds contradictions between semantically related markets

Data source: Polymarket Gamma API (public, read-only, no authentication required).

License

MIT