Palladium

A B-book trading platform for commodities and indices, built for a client. Correctness is enforced structurally: every money mutation flows through a single audited choke-point into an append-only, hash-chained ledger that is the source of truth.

• Single audited choke-point for all money movement — the ledger is truth, caches only mirror it.
• Append-only, hash-chained ledger (tamper-evident; gaps detectable via monotonic sequence).
• Per-instrument margin, liquidation and PnL.
• Queue-batched writer keeps the hot path off the database — no data loss under load.

• Choke-point → durable queue (BullMQ) → batched writer
• Hash-chained ledger + PostgreSQL of record
• Real-time price feed feeding margin/liquidation