Market data - Bayse Markets

Overview

The /ws/v1/markets endpoint streams real-time market data. No authentication is required.

wss://socket.bayse.markets/ws/v1/markets

Four subscription types are available:

Subscription	Channel	Server event type	Description
Activity feed	`activity`	`buy_order`, `sell_order`	Buy and sell order activity for an event.
Price updates	`prices`	`price_update`	Market price changes for an event.
Orderbook	`orderbook`	`orderbook_update`	Order book snapshots for a market.
User trades	`user_trades`	`buy_order`, `sell_order`	Trade activity for a specific user across all markets.

Activity feed

Subscribe to trade activity for a prediction event. Optionally filter by a specific market.

{
  "type": "subscribe",
  "channel": "activity",
  "eventId": "EVENT_ID"
}

To filter activity to a specific market within the event:

{
  "type": "subscribe",
  "channel": "activity",
  "eventId": "EVENT_ID",
  "marketId": "MARKET_ID"
}

Room names: activity:<eventId> or activity:<eventId>:<marketId>

Events received

buy_order — A buy order was filled.

{
  "type": "buy_order",
  "data": {
    "user": {
      "id": "usr_8b5c3c3a",
      "tag": "prediction_pro",
      "imageUrl": "https://cdn.bayse.markets/users/8b5c3c3a.png"
    },
    "order": {
      "id": "ord_7f5e2a1c",
      "amount": 100.00,
      "quantity": 150.0,
      "price": 0.65,
      "status": "FILLED",
      "type": "BUY",
      "outcome": "YES",
      "outcomeLabel": "Yes",
      "currency": "USD",
      "createdAt": "2026-02-17T10:30:00Z",
      "updatedAt": "2026-02-17T10:30:01Z"
    },
    "event": {
      "id": "evt_123",
      "slug": "us-fed-rate-cut-2026",
      "title": "Will the Fed cut rates in 2026?",
      "type": "SINGLE_MARKET",
      "createdAt": "2026-01-10T09:00:00Z",
      "imageUrl": "https://cdn.bayse.markets/events/fed.png"
    },
    "market": {
      "id": "mkt_456",
      "title": "Yes or No",
      "imageUrl": null
    }
  },
  "timestamp": 1700000000000
}

sell_order — A sell order was filled.

{
  "type": "sell_order",
  "data": {
    "user": { "id": "usr_9a1d2f4b", "tag": null, "imageUrl": null },
    "order": {
      "id": "ord_aa12bb34",
      "amount": 50.00,
      "quantity": 80.0,
      "price": 0.70,
      "status": "FILLED",
      "type": "SELL",
      "outcome": "YES",
      "outcomeLabel": "Yes",
      "currency": "USD",
      "createdAt": "2026-02-17T10:35:00Z",
      "updatedAt": "2026-02-17T10:35:01Z"
    },
    "event": { "id": "evt_123", "slug": "us-fed-rate-cut-2026", "title": "Will the Fed cut rates in 2026?", "type": "SINGLE_MARKET", "createdAt": "2026-01-10T09:00:00Z", "imageUrl": "https://cdn.bayse.markets/events/fed.png" },
    "market": { "id": "mkt_456", "title": "Yes or No", "imageUrl": null }
  },
  "timestamp": 1700000000000
}

quantity is floored. createdAt and updatedAt are ISO 8601 strings.

Unsubscribe

{ "type": "unsubscribe", "room": "activity:EVENT_ID" }

For a market-specific subscription:

{ "type": "unsubscribe", "room": "activity:EVENT_ID:MARKET_ID" }

Price updates

Subscribe to price changes for all markets in a prediction event.

{
  "type": "subscribe",
  "channel": "prices",
  "eventId": "EVENT_ID"
}

Room name: prices:<eventId>

Events received

price_update — A market price changed. The data field contains the full event snapshot. Example (trimmed):

{
  "type": "price_update",
  "data": {
    "id": "evt_123",
    "slug": "us-fed-rate-cut-2026",
    "title": "Will the Fed cut rates in 2026?",
    "status": "open",
    "type": "SINGLE_MARKET",
    "markets": [
      {
        "id": "mkt_456",
        "question": "Yes or No?",
        "outcomes": ["Yes", "No"],
        "engine": "CLOB",
        "prices": { "YES": 0.65, "NO": 0.35 }
      }
    ]
  },
  "timestamp": 1700000000000
}

Unsubscribe

{ "type": "unsubscribe", "room": "prices:EVENT_ID" }

Orderbook updates

Subscribe to order book snapshots for specific markets. Snapshots reflect the current state of bids and asks.

{
  "type": "subscribe",
  "channel": "orderbook",
  "marketIds": ["MARKET_ID"]
}

To receive orderbook data in a specific currency:

{
  "type": "subscribe",
  "channel": "orderbook",
  "marketIds": ["MARKET_ID"],
  "currency": "NGN"
}

marketIds supports up to 10 markets per subscription. The currency field accepts USD or NGN.

Room names: orderbook:<marketId> or orderbook:<marketId>:<currency>

Events received

orderbook_update — The order book snapshot was updated.

{
  "type": "orderbook_update",
  "data": {
    "orderbook": {
      "marketId": "mkt_456",
      "outcomeId": "out_789",
      "timestamp": "2026-02-17T10:40:00Z",
      "bids": [
        { "price": 0.60, "quantity": 500, "total": 300.0 },
        { "price": 0.55, "quantity": 300, "total": 165.0 }
      ],
      "asks": [
        { "price": 0.65, "quantity": 200, "total": 130.0 },
        { "price": 0.70, "quantity": 400, "total": 280.0 }
      ],
      "lastTradedPrice": 0.65,
      "lastTradedSide": "BUY"
    }
  },
  "timestamp": 1700000000000
}

Unsubscribe

For USD (default):

{ "type": "unsubscribe", "room": "orderbook:MARKET_ID" }

For NGN:

{ "type": "unsubscribe", "room": "orderbook:MARKET_ID:NGN" }

User trades

Subscribe to a specific user’s trade activity across all markets. Receives buy_order and sell_order events whenever the user’s orders are filled, regardless of the market engine (CLOB or AMM). To get a user’s ID from their tag, use the Lookup user endpoint.

{
  "type": "subscribe",
  "channel": "user_trades",
  "userId": "USER_ID"
}

Room name: user_trades:<userId>

Events received

buy_order / sell_order — The user’s order was filled.

{
  "type": "buy_order",
  "data": {
    "payload": {
      "user": {
        "id": "68eea9d8-a0fe-4534-ae88-b71e2f4f5c8f",
        "tag": "mulumba",
        "imageUrl": "https://cdn.bayse.markets/profile-images/mulumba.png"
      },
      "order": {
        "id": "7f5e2a1c-3b4d-4e6f-8a9b-1c2d3e4f5a6b",
        "amount": 100.00,
        "quantity": 150,
        "price": 0.65,
        "status": "FILLED",
        "type": "BUY",
        "outcome": "YES",
        "outcomeLabel": "Yes",
        "currency": "USD",
        "engine": "CLOB",
        "orderType": "MARKET",
        "createdAt": "2026-02-17T10:30:00Z",
        "updatedAt": "2026-02-17T10:30:01Z"
      },
      "event": {
        "id": "a1b2c3d4-5e6f-7a8b-9c0d-1e2f3a4b5c6d",
        "slug": "arsenal-trophyless-2026",
        "title": "Will Arsenal Go Trophyless This Season?",
        "type": "SINGLE_MARKET",
        "createdAt": "2026-01-10T09:00:00Z",
        "imageUrl": "https://cdn.bayse.markets/events/arsenal.png"
      },
      "market": {
        "id": "b2c3d4e5-6f7a-8b9c-0d1e-2f3a4b5c6d7e",
        "title": "Yes or No",
        "imageUrl": null
      }
    }
  },
  "timestamp": 1700000000000
}

Unsubscribe

{ "type": "unsubscribe", "channel": "user_trades", "userId": "USER_ID" }

Full example

const ws = new WebSocket("wss://socket.bayse.markets/ws/v1/markets");

ws.addEventListener("open", () => {
  // Subscribe to multiple channels
  ws.send(JSON.stringify({
    type: "subscribe",
    channel: "activity",
    eventId: "EVENT_ID"
  }));

  ws.send(JSON.stringify({
    type: "subscribe",
    channel: "prices",
    eventId: "EVENT_ID"
  }));

  ws.send(JSON.stringify({
    type: "subscribe",
    channel: "orderbook",
    marketIds: ["MARKET_ID"],
    currency: "USD"
  }));
});

ws.addEventListener("message", (event) => {
  for (const line of event.data.split("\n")) {
    if (!line.trim()) continue;
    const msg = JSON.parse(line);

    switch (msg.type) {
      case "buy_order":
      case "sell_order":
        console.log("Trade:", msg.data);
        break;
      case "price_update":
        console.log("Price:", msg.data);
        break;
      case "orderbook_update":
        console.log("Orderbook:", msg.data);
        break;
    }
  }
});

import asyncio
import json
import websockets

async def stream_market_data(event_id, market_id):
    async with websockets.connect("wss://socket.bayse.markets/ws/v1/markets") as ws:
        # Subscribe to multiple channels
        await ws.send(json.dumps({
            "type": "subscribe",
            "channel": "activity",
            "eventId": event_id,
        }))
        await ws.send(json.dumps({
            "type": "subscribe",
            "channel": "prices",
            "eventId": event_id,
        }))
        await ws.send(json.dumps({
            "type": "subscribe",
            "channel": "orderbook",
            "marketIds": [market_id],
            "currency": "USD",
        }))

        async for message in ws:
            for line in message.split("\n"):
                if not line.strip():
                    continue
                msg = json.loads(line)

                if msg["type"] in ("buy_order", "sell_order"):
                    print("Trade:", msg["data"])
                elif msg["type"] == "price_update":
                    print("Price:", msg["data"])
                elif msg["type"] == "orderbook_update":
                    print("Orderbook:", msg["data"])

asyncio.run(stream_market_data("EVENT_ID", "MARKET_ID"))

package main

import (
	"encoding/json"
	"fmt"
	"log"
	"strings"

	"github.com/gorilla/websocket"
)

func main() {
	conn, _, err := websocket.DefaultDialer.Dial(
		"wss://socket.bayse.markets/ws/v1/markets", nil,
	)
	if err != nil {
		log.Fatal(err)
	}
	defer conn.Close()

	eventID := "EVENT_ID"
	marketID := "MARKET_ID"

	conn.WriteJSON(map[string]any{
		"type":    "subscribe",
		"channel": "activity",
		"eventId": eventID,
	})
	conn.WriteJSON(map[string]any{
		"type":    "subscribe",
		"channel": "prices",
		"eventId": eventID,
	})
	conn.WriteJSON(map[string]any{
		"type":      "subscribe",
		"channel":   "orderbook",
		"marketIds": []string{marketID},
		"currency":  "USD",
	})

	for {
		_, data, err := conn.ReadMessage()
		if err != nil {
			log.Fatal(err)
		}
		for _, line := range strings.Split(string(data), "\n") {
			if strings.TrimSpace(line) == "" {
				continue
			}
			var msg map[string]any
			json.Unmarshal([]byte(line), &msg)
			fmt.Printf("%s: %v\n", msg["type"], msg["data"])
		}
	}
}

​Overview

​Activity feed

​Subscribe

​Events received

​Unsubscribe

​Price updates

​Subscribe

​Events received

​Unsubscribe

​Orderbook updates

​Subscribe

​Events received

​Unsubscribe

​User trades

​Subscribe

​Events received

​Unsubscribe

​Full example

Overview

Activity feed

Subscribe

Events received

Unsubscribe

Price updates

Subscribe

Events received

Unsubscribe

Orderbook updates

Subscribe

Events received

Unsubscribe

User trades

Subscribe

Events received

Unsubscribe

Full example