Markets WebSocket
The Markets WebSocket endpoint provides real-time market data including order book updates, price changes, and trade notifications.
Endpoint
wss://api.polymarket.us/v1/ws/markets
Subscription Types
| Value | Type | Description |
|---|
| 1 | MARKET_DATA | Full order book and market stats |
| 2 | MARKET_DATA_LITE | Lightweight price data only |
| 3 | TRADE | Real-time trade notifications |
Market Data Subscription
Subscribe to Full Market Data
{
"subscribe": {
"request_id": "md-sub-1",
"subscription_type": 1,
"market_slugs": ["market-slug-1", "market-slug-2"]
}
}
Market Data Response
Full order book with market statistics:
{
"request_id": "md-sub-1",
"subscription_type": 1,
"market_data": {
"market_slug": "market-slug-1",
"bids": [
{"px": {"value": "0.54", "currency": "USD"}, "qty": "1000"},
{"px": {"value": "0.53", "currency": "USD"}, "qty": "2500"}
],
"offers": [
{"px": {"value": "0.56", "currency": "USD"}, "qty": "800"},
{"px": {"value": "0.57", "currency": "USD"}, "qty": "1500"}
],
"state": 1,
"stats": {
"last_trade_px": {"value": "0.55", "currency": "USD"},
"shares_traded": "150000",
"open_interest": "500000",
"high_px": {"value": "0.58", "currency": "USD"},
"low_px": {"value": "0.52", "currency": "USD"}
},
"transact_time": "2024-01-15T10:30:00Z"
}
}
Market Data Lite Subscription
Subscribe to Lightweight Data
For reduced bandwidth, use the lite subscription:
{
"subscribe": {
"request_id": "mdl-sub-1",
"subscription_type": 2,
"market_slugs": ["market-slug-1"]
}
}
Market Data Lite Response
{
"request_id": "mdl-sub-1",
"subscription_type": 2,
"market_data_lite": {
"market_slug": "market-slug-1",
"current_px": {"value": "0.55", "currency": "USD"},
"last_trade_px": {"value": "0.55", "currency": "USD"},
"best_bid": {"value": "0.54", "currency": "USD"},
"best_ask": {"value": "0.56", "currency": "USD"},
"bid_depth": 5,
"ask_depth": 4,
"shares_traded": "150000",
"open_interest": "500000"
}
}
Trade Subscription
Subscribe to Trades
{
"subscribe": {
"request_id": "trade-sub-1",
"subscription_type": 3,
"market_slugs": ["market-slug-1"]
}
}
Trade Response
{
"request_id": "trade-sub-1",
"subscription_type": 3,
"trade": {
"market_slug": "market-slug-1",
"price": {"value": "0.55", "currency": "USD"},
"quantity": {"value": "100", "currency": "USD"},
"trade_time": "2024-01-15T10:30:00Z",
"maker": {
"side": 1,
"intent": 1
},
"taker": {
"side": 2,
"intent": 2
}
}
}
Market States
| Value | State | Description |
|---|
| 1 | OPEN | Market open for trading |
| 2 | PREOPEN | Market in pre-open phase |
| 3 | SUSPENDED | Trading temporarily suspended |
| 4 | HALTED | Trading halted |
| 5 | EXPIRED | Market has expired |
| 6 | TERMINATED | Market terminated |
Debouncing
For high-frequency markets, enable response debouncing to reduce message volume:
{
"subscribe": {
"request_id": "md-sub-1",
"subscription_type": 1,
"market_slugs": ["market-slug-1"],
"responses_debounced": true
}
}
Subscription LimitsYou can subscribe to a maximum of 100 markets per subscription. Use multiple subscriptions if you need more.
Order Book Depth
The full market data subscription includes the top levels of the order book. Each level shows:
| Field | Description |
|---|
px | Price level |
qty | Total quantity at this price |
