Gamma API
Polymarket's market-discovery REST API at gamma-api.polymarket.com, used to list markets, fetch metadata, and poll resolution status.
Definition
The Gamma API (gamma-api.polymarket.com) is Polymarket's public REST API for market metadata. It exposes market questions, outcome token IDs, start and end times, current prices, and resolution status. It also serves as the authoritative source for whether a market has closed and which outcome won, making it the correct place to poll for Chainlink oracle resolution.
In practice
All predtools bots call the Gamma API on startup to find the active 5-minute BTC or ETH binary market for the current window. The resolveViaGamma() helper polls the Gamma API until an outcome token price reaches $0.99 or above, confirming resolution. This avoids relying on Binance price (which may differ from the Chainlink oracle used by Polymarket) to determine win/loss. The Gamma API requires no authentication for read operations.