The Polymarket US API is split into two parts: an authenticated API for trading and a public API for reading market data. For support, contact support@polymarket.us.
Use the authenticated API to trade. This is where you place orders, check your positions, and manage your account. Every request requires an API key - see Authentication to get set up.
Group
What you get
Orders
Place, modify, cancel, and query orders
Portfolio
View positions and trading activity
Account
Check balances and buying power
The authenticated API also provides two WebSocket endpoints for real-time streaming:
Use the public API to browse what’s available on Polymarket US. No API key needed. This is where you fetch markets, events, series, sports data, and search results. If you’re building something that displays market information - prices, odds, order books - this is all you need.
Group
What you get
Markets
List markets, get order books, BBO, settlement prices