Market Data Streams

Real-time price feeds, candles, trades, and order books

Ticker Stream

Get 24-hour statistics updated every 200ms.

Subscribe

{
  "method": "subscribe",
  "subscription": [{
    "type": "ticker",
    "symbol": "BTC-USD"
  }]
}

Update Frequency: Every 200ms

Ticker Fields:

Field	Description
priceChange	Absolute price change over 24h
priceChangePercent	Percentage price change over 24h
lastPrice	Last traded price
highPrice	24h high
lowPrice	24h low
volume	24h base asset volume
quoteVolume	24h quote asset volume
markPrice	Current fair/mark price
oraclePrice	Oracle-reported price
openInterest	Total open interest
fundingRate	Current funding rate
regime	Market regime indicator (-1, 0, 1)
regimeDt	Regime duration in 10s intervals
regimeVol	Regime-adjusted volatility
regimeMv	Regime mean value
fairBookPx	Fair price derived from order book
fairVol	Fair volatility estimate
fairBias	Fair price bias
timestamp	Timestamp (nanoseconds)

---

Candles Stream

Real-time candlestick data with historical backfill.

Subscribe

{
  "method": "subscribe",
  "subscription": [{
    "type": "candle",
    "symbol": "BTC-USD",
    "interval": "1m"
  }]
}

Supported Intervals: 10s, 1m, 3m, 5m, 15m, 30m, 1h, 2h, 4h, 6h, 8h, 12h, 1d, 3d, 1w, 1M

Initial Response: Up to 5000 historical candles

Updates: Real-time (10s instant; larger intervals aggregated ~10–20s)

Candle Fields:

Field	Description
t	Open timestamp (milliseconds)
T	Close timestamp (milliseconds)
o	Open price
h	High price
l	Low price
c	Close price
v	Volume
n	Number of trades

---

Trades Stream

Real-time trades feed

Subscribe

{
  "method": "subscribe",
  "subscription": [{
    "type": "trades",
    "symbol": "BTC-USD"
  }]
}

Initial Response: None (stateless)

Updates: Real-time on every fill

Trade Fields:

Field	Description
s	Symbol (market)
px	Execution price
sz	Size traded
time	Timestamp (milliseconds)
side	true if taker bought, false if taker sold
maker	Maker public key (base58)
taker	Taker public key (base58)
reason	Fill reason (optional; only present if not a normal trade, e.g. "liquidation", "adl")
liq	Liquidation flag (optional; only present if true)

---

L2 Snapshot Stream

Periodic full order book snapshots.

Subscribe

{
  "method": "subscribe",
  "subscription": [{
    "type": "l2Snapshot",
    "symbol": "BTC-USD",
    "nlevels": 10,
    "aggregation": 0.5
  }]
}

Parameters:

• nlevels (optional): Number of price levels per side
• aggregation (optional): Price bucket size in quote currency

Update Frequency: Every 200ms

Structure: levels[0] = bids (descending), levels[1] = asks (ascending)

---

L2 Delta Stream

Real-time incremental order book updates with initial snapshot.

L2 Delta sends an initial snapshot (latest cached book state) on subscription, then real-time delta updates for every price level change.

Subscribe

{
  "method": "subscribe",
  "subscription": [{
    "type": "l2Delta",
    "symbol": "BTC-USD"
  }]
}

Initial Response: Latest cached book state (if available)

Updates: Real-time on every price level change

Delta Format:

• Each delta update contains changes to a single price level
• Only ONE side (bids or asks) will have levels per update (the other is empty [])
• levels[0] = bids (highest to lowest)
• levels[1] = asks (lowest to highest)
• Each level: {px, sz, n} where n is always 0 for deltas
• sz: 0 means remove the level

---

Risk Metrics Stream

Subscribe to risk metrics for a symbol. Risk metrics include maintenance-margin surfaces (buy/sell grids over notional and leverage) and asset correlations.

Subscribe

{
  "method": "subscribe",
  "subscription": [{
    "type": "risk",
    "symbol": "BTC-USD"
  }]
}

Initial Response: Latest cached risk metrics (if available)

Updates: Event-driven (only when asset risk changes)

Risk Metrics Fields:

Field	Description
symbol	Market symbol
timestamp	Timestamp in milliseconds
regime	Risk regime index (-12 to 12)
leverage	Array of leverage knot points (e.g. 1.0 … 50.0)
notionals	Array of notional knot points (e.g. 50000 … 10000000)
buy	2D array of risk points [notional_idx][leverage_idx] for buy side
sell	2D array of risk points [notional_idx][leverage_idx] for sell side
corrs	Array of [pair, correlation] tuples (e.g. ["BTC:ETH", 0.71])

Buy/sell point fields (each cell in the grid):

Field	Description
mmrO	Start-of-regime maintenance margin ratio
mmrE	End-of-regime maintenance margin ratio
p	Probability of remaining in the regime

Surface indexing: To get the risk point for a given notional and leverage, find the notional bracket in notionals, the leverage bracket in leverage, then use buy[notional_idx][leverage_idx] or sell[notional_idx][leverage_idx]. Interpolate between surrounding grid points if needed.

---

Frontend Context Stream

Aggregated market context for all symbols. Ideal for dashboard views.

Subscribe

{
  "method": "subscribe",
  "subscription": [{
    "type": "frontendContext"
  }]
}

Initial Response: Latest cached ticker data for all symbols

Updates: Every 2 seconds

Context Fields:

Field	Description
symbol	Market symbol
volume	24h trading volume (base currency)
funding	Current funding rate
oi	Open interest (base currency)
lastPrice	Last traded price
priceChange	24h price change (absolute)
priceChangePercent	24h price change (percentage)

---

Multiple Subscriptions

Subscribe to multiple streams at once:

{
  "method": "subscribe",
  "subscription": [
    {"type": "ticker", "symbol": "BTC-USD"},
    {"type": "trades", "symbol": "BTC-USD"},
    {"type": "candle", "symbol": "BTC-USD", "interval": "1m"},
    {"type": "l2Snapshot", "symbol": "BTC-USD", "nlevels": 20},
    {"type": "l2Delta", "symbol": "BTC-USD"},
    {"type": "risk", "symbol": "BTC-USD"},
    {"type": "frontendContext"}
  ]
}

Response:

{
  "type": "subscriptionResponse",
  "topics": [
    "ticker.BTC-USD",
    "trades.BTC-USD",
    "candle.BTC-USD.1m",
    "l2snapshot.BTC-USD",
    "l2delta.BTC-USD",
    "risk.BTC-USD",
    "frontendContext"
  ]
}

---

Example Implementation

Node.js

const WebSocket = require('ws');

const ws = new WebSocket('wss://exchange-ws1.bulk.trade');

ws.on('open', () => {
  console.log('Connected to Bulk Exchange');
  
  // Subscribe to multiple streams
  ws.send(JSON.stringify({
    method: 'subscribe',
    subscription: [
      { type: 'ticker', symbol: 'BTC-USD' },
      { type: 'trades', symbol: 'BTC-USD' },
      { type: 'frontendContext' }
    ]
  }));
});

ws.on('message', (data) => {
  const message = JSON.parse(data);
  
  if (message.type === 'subscriptionResponse') {
    console.log('Subscribed to:', message.topics);
    return;
  }
  
  switch(message.type) {
    case 'ticker':
      console.log('Ticker:', message.data.ticker);
      break;
    case 'trades':
      console.log('Trade:', message.data.trades);
      break;
    case 'frontendContext':
      console.log('Context:', message.data.ctx);
      break;
  }
});

ws.on('error', (error) => {
  console.error('WebSocket error:', error);
});