/ orderbook price-time-priority matching engine · real C++ compiled to WebAssembly
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New here? This is a real C++ matching engine running live in your browser — watch the
market, then open Execution to work an order or Strategies to pit trading
bots against each other. Fire a news shock any time.
last—
bid—
ask—
spread—
regime—
volatility
Order book depth and recent trades
pricesize
time & salessize
your working orders
Click or focus a ladder level and press enter to rest an order (bid side buys, ask side sells) · your fills push the price (market impact) · fire a news shock or turn up turbulence · space pauses
| strategy | order | avg px | slippage | fill | mid Δ | time |
|---|
Work a parent order through the live book. Slippage is the realized average price vs the mid at arrival (negative = a cost); mid Δ is how far the mid moved over the fill window (your impact plus market drift). Run the same order a few times to compare strategies.
scenario
Market makerquotes both sides, earns the spread, fears inventory
P&L$0.00
inventory0
spread — · adverse — · quotes —/—
Momentumbuys strength, sells weakness — rides trends, whipsaws in chop
P&L$0.00
position0
signal
Mean reversionfades moves back to the mean — wins ranges, bleeds in trends
P&L$0.00
position0
signal
Cumulative P&L of each running bot. Pick a scenario and watch who wins: momentum in trends, mean reversion in choppy markets, the maker on spread until adverse selection bites.