Design an Order Matching Engine

Design the core matching engine of a single exchange venue. Members send limit and market orders and cancels; the engine matches by price-time priority per symbol, emits executions and market data, and must recover exactly from failure. Focus on the single-threaded deterministic core, the sequenced input log, recovery and failover, latency, and the risk-check and market-data paths around it. Out of scope: clearing and settlement, the brokerage front end, and wallets/custody (see the stock trading and crypto exchange problems).