> ## Documentation Index
> Fetch the complete documentation index at: https://docs.delphimarkets.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Polymarket WebSocket

> Real-time price, orderbook, and trade streaming for Polymarket

## Connection

Connect to the Polymarket WebSocket endpoint:

```
wss://api.delphiterminal.co/ws/poly
```

No authentication is required for WebSocket connections.

| Property         | Value                   |
| ---------------- | ----------------------- |
| Protocol         | WebSocket (wss\://)     |
| Keepalive        | Ping every 54 seconds   |
| Timeout          | 60 seconds without pong |
| Max Message Size | 512 KB                  |

## Subscribing to markets

Once connected, send a JSON message to subscribe using `condition_id`:

```json theme={"theme":"one-dark-pro"}
{
  "action": "subscribe",
  "condition_ids": ["0x00000977017fa72fb6b1908ae694000d3b51f442c2552656b10bdbbfd16ff707"],
  "message_types": ["prices", "orderbook", "trades"]
}
```

| Field           | Type   | Required | Description                                                                                                  |
| --------------- | ------ | -------- | ------------------------------------------------------------------------------------------------------------ |
| `action`        | string | Yes      | `subscribe` or `unsubscribe`                                                                                 |
| `condition_ids` | array  | Yes      | Array of Polymarket condition identifiers (hex strings starting with 0x)                                     |
| `message_types` | array  | No       | `["prices"]`, `["orderbook"]`, `["trades"]`, or any combination. Defaults to prices and orderbook if omitted |

## Unsubscribing

```json theme={"theme":"one-dark-pro"}
{
  "action": "unsubscribe",
  "condition_ids": ["0x00000977017fa72fb6b1908ae694000d3b51f442c2552656b10bdbbfd16ff707"]
}
```

## Message types

### Price messages

Real-time price updates for subscribed markets:

```json theme={"theme":"one-dark-pro"}
{
  "type": "prices",
  "data": {
    "exchange": "poly",
    "condition_id": "0x0000097701...",
    "price": 0.992,
    "last_update": "2026-02-04T15:30:00Z"
  }
}
```

### Orderbook messages

Real-time orderbook snapshots for subscribed markets:

```json theme={"theme":"one-dark-pro"}
{
  "type": "orderbook",
  "data": {
    "snapshot_time": "2026-02-04T15:30:00Z",
    "exchange": "poly",
    "market_id": "0x1234abcd...",
    "condition_id": "0x0000097701...",
    "bid_side": [0.55, 0.54, 0.53, 0.52, 0.51],
    "ask_side": [0.56, 0.57, 0.58, 0.59, 0.60],
    "original_last_update": "2026-02-04T15:29:59Z"
  }
}
```

### Trade messages

Real-time trade executions for subscribed markets:

```json theme={"theme":"one-dark-pro"}
{
  "type": "trades",
  "data": {
    "exchange": "poly",
    "condition_id": "0x0000097701...",
    "token_id": "0x123...",
    "market_id": "0xabc...",
    "price": 0.65,
    "size": 100.5,
    "side": "buy",
    "last_update": "2026-02-04T15:30:00Z"
  }
}
```

## Full example

```javascript theme={"theme":"one-dark-pro"}
const ws = new WebSocket("wss://api.delphiterminal.co/ws/poly");

ws.onopen = () => {
  console.log("Connected to Polymarket WebSocket");

  ws.send(JSON.stringify({
    action: "subscribe",
    condition_ids: ["0x00000977017fa72fb6b1908ae694000d3b51f442c2552656b10bdbbfd16ff707"],
    message_types: ["prices", "orderbook", "trades"]
  }));
};

ws.onmessage = (event) => {
  const data = JSON.parse(event.data);

  if (data.type === "prices") {
    console.log("Price update:", data.data);
  } else if (data.type === "orderbook") {
    console.log("Orderbook update:", data.data);
  } else if (data.type === "trades") {
    console.log("Trade:", data.data);
  }
};

ws.onclose = () => console.log("Disconnected");
ws.onerror = (error) => console.error("WebSocket error:", error);
```

## Important notes

* **No authentication required** for WebSocket connections
* Use `condition_id` (Polymarket condition identifier) to subscribe
* Messages are only sent for markets you have explicitly subscribed to
* Multiple markets can be subscribed in a single message
* Trades must be explicitly requested (not included in the default subscription)
* Orderbook updates are high-frequency — consider filtering client-side if needed