Order lifecycle · pre-trade risk · recovery
📖 OMS
Notes on the broker-side Order Management System — where the OMS sits in the broker stack, the internal order state machine & FIX mapping, pre-trade risk checks, idempotency & consistency, mid-session recovery & reconciliation, the order-entry hot path and a reference architecture.
Sources: hands-on brokerage OMS build & operations notes · FIX 4.2/4.4 specification · Designing Data-Intensive Applications · public exchange connectivity guides.

