Liquidity heatmap

The liquidity heatmap shows where limit orders rested over time. Each price level is a thin horizontal line whose brightness is the resting size. Walls glow, thin liquidity fades, and you can see orders arrive, sit and get pulled or filled.

How it is recorded

Flowscope keeps the exact order book of every open market live: a snapshot plus every change from the venue’s websocket, with the venue’s sequence checks.

From that book it records each price bucket’s resting size at the close of every minute, stored as runs:

(start, duration, price bucket, quantity, side)

• A price bucket is about 0.001 % of the price.
• A run is cut only where a bucket’s size at one minute’s close differs from the minute before, so a level that rests for hours is one run, not a snapshot per minute.
• The minute that is forming shows the book as it stands; once it closes, it keeps what stood at its close.
• A gap in the venue’s sequence, or a dropped connection, ends every run at that instant, clears the book and resynchronizes. Nothing is invented to fill the gap.

What this gives up, by choice, is whatever happens inside a minute: an order that came and went within it, such as the one that sat for 400 ms or the wall pulled and re-posted, is not in the record. On bars shorter than a minute the heatmap moves in minute steps.

How far above and below the price the heatmap reaches is how deep each venue publishes its book. For BTC (measured October 2026):

An aggregated market (All venues) sums them, so its heatmap reaches as far as the deepest venue in it. Coinbase is one of the venues BTC, ETH and the other majors sum by default, so walls thousands of dollars away show.

Adding it to a chart

The heatmap is the Liquidity Heatmap study. It is already on liquidity charts and the included Liquidity & execution layout. Add it to any chart from the indicator dialog (/), group Heatmaps.

The Liquidity (price line) chart type hides the bars entirely and leaves the heatmap and a price line. It is the cleanest way to read liquidity.

Settings

The floating range slider is the quickest control. Drag its left handle up to hide thin liquidity; drag the right handle down to saturate walls sooner. Its buttons turn auto levels on or off (the magic wand), switch between HD and SD, reset the range, switch between Lines and Classic, open the heatmap settings, or hide the slider. The slider appears when the chart is larger than about 380 × 160 px.

Styles

HD and SD

HD draws the finest bins: every price bucket on its own in Lines and the splats, and Classic cells as set. SD merges more of the book into each bin: four buckets into one filled row in Lines and the splats, and Classic cells twice as tall and twice as wide. HD suits short timeframes and precise reading, SD longer ones.

Low and peak size

With a peak size set, the colours no longer follow what is in view: sizes from the low size up are drawn, and the peak size and above at full colour. Use them to keep one scale while scrolling, or to compare charts. Both 0 (the default) measure the scale from the view.

Intensity is relative to what is on screen: a percentile of the visible sizes maps to full brightness. Zooming into a quiet area brings out structure that a busy area would drown.

Smooth panning

Rasterizing runs on an engine worker, never on the interface thread. A raster reaches past the plot on every side and is drawn again only when the view leaves that margin, the zoom changes or the book does. While a new image is on its way, the chart keeps drawing the last one mapped into the current view, so panning and zooming stay smooth.

When only the book changed, only the live part is drawn again: the columns from the minute that was forming at the last image on. The history in view stays as it was drawn, as a minute’s levels are its close’s. That takes about a millisecond where a whole image takes a hundred, so the heatmap follows the book live even in the browser. Every five seconds, and whenever history from the hub arrives, the image is drawn whole once. Zoomed far out, the hub sends its history at a coarser time resolution (down to one slot an hour), so a week in view loads and draws far fewer levels.

Trade bubbles

The Trade Bubbles study draws the largest market orders in view as circles sized by quantity, buys and sells in their own colours.

Order book profile

The Order Book Profile study draws the current book as horizontal bars at the right edge of the chart, bids and asks in their own colours. Its width defaults to 96 px.

Aggregated heatmaps

On an aggregated market the heatmap is drawn from the summed book of its venues. Each venue’s contribution is tracked separately, so a venue that resynchronizes or disconnects removes exactly what it added.

Markets of an indicator

The heatmap does not have to read the chart’s market. Markets in its settings opens the same picker as a pane’s: the coin’s venues in a perpetuals, a coin-margined and a spot column, each with All, the chart’s market marked current. Choose one market to see its heatmap on this chart, or several to see them summed: an aggregated heatmap of Binance, Bybit and OKX over a Binance chart. Chart’s market goes back to the chart’s own. The legend names the choice (Heatmap Viridis · 3 markets).

The Liquidation Heatmap, Trade Bubbles, the Order Book Profile and Liquidations have the same setting, and so do the indicators computed from bars: CVD, Delta Volume, Volume, Trade Counter, Open Interest, Net Positioning, OB Depth and Liquidation Volume. Those run on the bars of their markets at the chart’s interval and land on the chart’s bars by time (a CVD of its own markets draws their sum, not one line per venue). Bar Stats reads every row from its markets’ bars the same way, and the visible-range volume profile is built from their footprints over the time on screen. The footprint chart itself shows the chart’s market: open an aggregated market for a footprint of several venues. Each indicator keeps its own choice. When the chart turns to another coin, the same venues are taken for it, and venues that do not list the coin are left out.

The history of a summed choice is summed too. The hub records every venue’s heatmap; for a choice of venues it sums their recorded hours when the app asks for them, so the aggregated heatmap reaches back as far as its venues were recorded. Changing the choice draws the heatmap again from the new sum.

History

No venue publishes historical order books: heatmap history is what the data hub recorded, once a minute. The hub serves its recorder’s tiles for the hours before you opened the market, back as far as it recorded the market (make dev runs one; the browser app reaches it at /hub). The app keeps no heatmap on the machine: each session loads it from the hub again.

Related layers

• Liquidation heatmaps use the same raster with their own ramps: modelled liquidation levels, and measured Hyperliquid take-profits, stops and liquidations.
• The depth book shows the current book as a list with cumulative depth.