# Perp Gap API: prediction markets

## Prediction markets: Hyperliquid HIP-4 outcome odds vs perp-implied probability (x402)
Docs: https://perp-gap-api.perpgap.workers.dev/pm · OpenAPI: https://perp-gap-api.perpgap.workers.dev/pm/openapi.json · x402: https://perp-gap-api.perpgap.workers.dev/pm/x402.json
- [GET /pm/markets](https://perp-gap-api.perpgap.workers.dev/pm/markets): free. Live Hyperliquid binary price outcome markets ("BTC above 82,268 on Oct 18"): id, strike, expiry, settlement source, bid, ask, depth. Empty books filtered.
- [GET /pm/implied?asset=BTC](https://perp-gap-api.perpgap.workers.dev/pm/implied): $0.02. Every live market on one asset: bid/ask/depth vs the probability implied by the Hyperliquid perp mid and 7d realized vol, edge in pp vs bid and ask, liquidity flag, signal (yes_underpriced / yes_overpriced / fair / illiquid). Also ?outcome=<id>.
- [GET /pm/scan?min_edge_pp=2&max_spread_pp=10](https://perp-gap-api.perpgap.workers.dev/pm/scan): $0.05. All liquid markets ranked by edge (kind=crypto|stocks|all, min_depth_usd, limit).
- MCP tools: list_pm_markets (free), get_pm_implied ($0.02), get_pm_scan ($0.05).
- Bad input or no live market returns a free 400/404 before any payment. Every response carries bid, ask, depth and the label "data, not advice". Model: lognormal, zero drift, realized vol, no options data.