Order flow

What it is

Order flow is the study of who is hitting whom in the market — tracking, trade by trade, whether the buyer or the seller was the aggressor, and how much resting liquidity sits on either side of the spread. Every executed trade prints at either the bid or the ask: trades at the ask are buyer-initiated (someone lifted the offer), trades at the bid are seller-initiated (someone hit the bid). Aggregating that signed flow over time, across price levels, and against the visible order book is what order flow analysis is.

Order flow exists because price by itself is a lagging summary. A bar that closes green tells you the period ended higher than it started, but it tells you nothing about how that move happened — whether buyers paid up aggressively, whether sellers tried to push and got absorbed, whether one side suddenly stopped showing up. Order flow opens that black box.

Why it matters

Order flow gives you a different decision input than candlesticks or moving averages. You stop asking where is price going and start asking who is in control right now. That shifts the timeframe of useful information from minutes-to-hours down to seconds-to-minutes — which is exactly where intraday futures traders operate.

Practical uses include:

• Detecting absorption — strong directional volume that fails to move price, signalling passive size on the other side.
• Confirming or fading a breakout based on whether aggressive flow actually accompanies the move.
• Identifying exhaustion at session highs and lows when delta flips against the direction of price.
• Spotting one-sided liquidity (single prints, zero prints) that the market often revisits.

How traders use it on Sierra Chart

Sierra Chart is one of the most order-flow-native platforms available because it stores tick data with bid/ask classification and exposes it both through native chart types and through ACSIL studies. The two main surfaces are the Numbers Bars chart type, which renders per-bar bid/ask volume inside each bar as a footprint, and the Market Depth Historical data, which preserves the resting order book over time.

From there, traders typically layer derived signals — delta, CVD, footprint imbalances, depth heatmaps — either as chart panes, as in-bar overlays on Numbers Bars, or as alert conditions feeding their playbook.

Common patterns / pitfalls

• Order flow is a confirmation and timing tool, not a standalone signal. Trading every delta divergence without context will bleed.
• Bid/ask classification depends on tick-by-tick data quality. Reconstructed or aggregated feeds can corrupt the signal.
• Big absorption prints in thin overnight conditions usually mean nothing — the same print in RTH at a key level is often actionable.
• Order flow is most informative at structural levels (prior POC, VAH/VAL, session highs/lows), not in the middle of a range.

Related SCS studies

Several SCS studies surface order flow concepts directly on the chart — Delta Candle Color recolors bars by aggression balance, CVD Filled Area renders cumulative volume delta as a session-anchored area, and Single Print and Gap auto-detects one-sided footprint levels worth tracking.