OBV (On-Balance Volume)

OBV is a cumulative volume indicator that adds volume on up-days and subtracts volume on down-days. Rising OBV confirms an uptrend; divergence between OBV and price warns of potential reversals.

Declaration

function init(ctx) {
  ctx.indicator('obv', 'OBV', {});
}

Options

OBV requires no options. It uses close and volume data automatically.

Output

Returns a single number[] series (cumulative volume).

Accessing Values

function onBar(ctx, i) {
  const obv = ctx.ind.obv[i];
}

Use Cases

Trend Confirmation

function init(ctx) {
  ctx.indicator('obv', 'OBV', {});
  ctx.indicator('ema', 'EMA', { period: 21 });
}

function onBar(ctx, i) {
  const priceUp = ctx.series.close[i] > ctx.series.close[i - 10];
  const obvUp = ctx.ind.obv[i] > ctx.ind.obv[i - 10];
  
  // Price and OBV both rising = confirmed uptrend
  if (priceUp && obvUp) {
    ctx.order.market('ASSET', 1, { signal: 'buy', reason: 'obv_confirmed' });
  }
  
  // Price rising but OBV falling = bearish divergence
  if (priceUp && !obvUp) {
    ctx.order.close('ASSET', { signal: 'sell', reason: 'obv_divergence' });
  }
}

Calculation

If Close > Previous Close: OBV = Previous OBV + Volume
If Close < Previous Close: OBV = Previous OBV - Volume
If Close = Previous Close: OBV = Previous OBV

ADL - Accumulation/Distribution Line
MFI - Volume-weighted RSI
VWAP - Volume Weighted Average Price