Reading the Chart¶
Candlesticks — top panel¶
Each candle represents one minute of SPY trading in Eastern Time.
| Candle colour | Meaning |
|---|---|
| Green | Close above open (up-minute) |
| Red | Close below open (down-minute) |
The wicks show the high and low of the minute; the body shows the open-to-close range.
Imbalance markers¶
When the detection algorithm flags a candle, a marker is drawn directly on the chart:
▲ B Buy-heavy candle — buy volume in this minute significantly exceeded the recent rolling average, and buyers dominated sellers. Often coincides with aggressive institutional buying or short covering.
▼ S Sell-heavy candle — sell volume significantly exceeded the rolling average, and sellers dominated buyers. Can indicate distribution or momentum selling.
Tip
Not every large-volume candle gets a marker. Both conditions must be true simultaneously: the volume must exceed the rolling threshold and one side must dominate. See Detection Algorithm for exact rules.
Volume Delta panel — bottom panel¶
The lower panel shows the net order-flow delta for each minute.
| Bar colour | Meaning |
|---|---|
| Green bar | Buy volume > sell volume (net buying) |
| Red bar | Sell volume > buy volume (net selling) |
- Each bar height represents the absolute difference between buy and sell volume — taller = more aggressive one-sided flow.
- The zero baseline is always pinned to the bottom of the panel.
- The delta panel and the candlestick panel share the same time axis and zoom level.
Live indicator¶
A pulsing ● LIVE badge in the top-right corner of the chart confirms an active WebSocket connection to the backend. The chart updates automatically every BROADCAST_INTERVAL_S seconds (default: 2 s).
If the connection drops the badge disappears and the chart freezes — refresh the page to reconnect.