ctx.order.market()

Place a market order that fills at the next bar's open.

Signature

ctx.order.market(symbol, quantity, metadata?)

Parameters

Name	Type	Description
`symbol`	`string`	Asset symbol (typically `'ASSET'`)
`quantity`	`number`	Position size: 1 = full position, 0.5 = half, -1 = short
`metadata`	`object`	Optional order metadata

Quantity

1 = Full long position (100% of capital)
0.5 = Half position (50% of capital)
0.25 = Quarter position
-1 = Full short position
-0.5 = Half short position

Metadata Options

Option	Type	Description
`signal`	`string`	Signal name for analysis (`'buy'`, `'sell'`, etc.)
`reason`	`string`	Human-readable reason
`type`	`string`	Order type hint (`'full_entry'`, `'partial_entry'`)

Examples

Full entry

function onBar(ctx, i) {
  if (q.crossOver(ctx.ind.fastEma, ctx.ind.slowEma, i)) {
    ctx.order.market('ASSET', 1, { signal: 'buy', reason: 'ema_crossover' });
  }
}

Partial entries (scaling in)

function onBar(ctx, i) {
  const rsi = ctx.ind.rsi[i];
  
  if (rsi < 20) {
    // Extreme oversold: half position
    ctx.order.market('ASSET', 0.5, { signal: 'buy', type: 'partial_entry' });
  } else if (rsi < 30) {
    // Oversold: quarter position
    ctx.order.market('ASSET', 0.25, { signal: 'buy', type: 'partial_entry' });
  }
}

Short positions

Use negative quantity to open short positions. Your strategy must explicitly handle short entries and exits in its onBar function — the engine does not auto-invert long signals.

function onBar(ctx, i) {
  const tradingMode = ctx.p.tradingMode || 'LONG_ONLY';
  
  if (tradingMode === 'SHORT_ONLY') {
    // Enter short on bearish cross
    if (q.crossUnder(ctx.ind.fastEma, ctx.ind.slowEma, i)) {
      ctx.order.market('ASSET', -1, { signal: 'enterShort' });
    }
    // Exit short on bullish cross
    if (q.crossOver(ctx.ind.fastEma, ctx.ind.slowEma, i)) {
      ctx.order.close('ASSET', { signal: 'exitShort' });
    }
  }
}

Important: Strategies must natively implement the trading modes they support. The engine does not auto-invert signals. Unsupported modes are locked in the UI. See the Trading Modes guide under Best Practices for full details.

Fill Timing

Market orders fill on the next bar's open:

Bar i: close = 100, onBar places market order
Bar i+1: open = 101 → Order fills at 101 (± slippage)

Slippage

Slippage is applied based on backtest configuration:

Fill Price = Next Bar Open × (1 + slippage × direction)

Where direction is +1 for buys (slippage works against you), -1 for sells.

ctx.order.close() — Close position
ctx.order.reduce() — Partial exit
Market Fill Rules — Engine execution