Betfair Steam Move Detector

Weight of Money (WoM)Ratio of available-to-back vs available-to-lay at best prices. WoM > threshold = more backing than laying = price likely to shorten.

Tick VelocityRate of price shortening on the Betfair tick ladder. A steam move shortens N+ ticks within a fixed time window — the faster the move, the stronger the signal.

Signal ConfirmationBoth conditions must align: sustained WoM dominance AND rapid tick shortening. One alone is noise — both together is steam.

Steam signals

Drift signals

Total ticks processed

0:00

Market time

WoM threshold 68%

Tick velocity (ticks/10s) 4

Market volatility Medium

Signal Log

Detection Algorithm

1. WoM GateWoM at best prices > threshold for 3 consecutive ticks

2. Velocity GatePrice shortened by ≥ N ticks in last 10 seconds on Betfair ladder

3. ConfirmationBoth conditions true simultaneously → STEAM signal fires

4. Drift MirrorWoM < (100 − threshold) AND price lengthening → DRIFT signal

5. Cooldown8-second lockout per runner after any signal fires

About this demo

A steam move is a sudden, coordinated shortening of a Betfair price driven by a concentration of backing activity. This detector fires when two conditions are true simultaneously: the Weight of Money ratio exceeds a dominance threshold (more backing volume than laying), and the rate of tick shortening over a rolling window exceeds a velocity threshold.

Requiring both signals to be present together filters out normal price drift from genuine steam. Adjust the WoM and velocity sliders to see how threshold sensitivity changes the signal rate, or use the manual inject button to fire a forced steam event and observe how the detector responds. In a live trading system this signal typically triggers within one to three ticks of coordinated activity.

Signal: WoM Dominance + Tick Velocity Technology: Java · Betfair Streaming API · Spring Boot Read: Weight of Money in Java →