Quantum Trading Terminal

The problem

Quantum Finance's legacy trading platform was bleeding latency. Average order-to-acknowledgement time exceeded 18 milliseconds — an eternity in modern electronic trading. Worse, the monolithic C# codebase had accumulated a decade of technical debt: deploys took 45 minutes, hotfixes regularly caused outages, and adding new asset classes required touching 200+ files. The team was spending more time keeping the lights on than shipping features.

Research

We spent three weeks embedded with the trading desk, compliance team, and engineering org. We shadowed traders during market open and close, profiled the existing system under load, and benchmarked competitor platforms. The research surfaced three non-negotiables: sub-2ms acknowledgement latency, zero data loss on failover, and a deployment pipeline that wouldn't require a 4am maintenance window.

Design & architecture

We designed a streaming-first architecture: a custom Rust gateway handling FIX protocol ingestion, an event spine built on Aeron for ultra-low-latency messaging, and a TypeScript-based trader UI rendered with WebGL. State was persisted to a tiered storage layer — in-memory for hot data, Redis for warm, PostgreSQL for cold. Every component was designed to be independently deployable and horizontally scalable.

Development

We staffed a 7-person squad: 3 Rust engineers, 2 TypeScript engineers, 1 SRE, and 1 PM. Sprints were two weeks. Every Friday, the trading desk demoed new functionality against a sandboxed market replay. Code reviews were mandatory on every PR. Property-based testing and chaos engineering were baked into CI from week one — not bolted on at the end.

Testing & deployment

Before launch, we ran 6 weeks of parallel operation: every order routed through both the legacy and new systems, with automated reconciliation. We simulated market crashes, network partitions, and three-region failover. When the cutover finally happened, it was anti-climactic — the new platform simply took over, and nobody on the trading desk noticed until the latency dashboards updated.

Business outcome

Within 90 days of launch, Quantum Finance had onboarded 18,500 new users — a 35% increase in their active trader base. Average latency dropped from 18ms to 5.8ms. The platform has run at 99.97% availability for 14 consecutive months. The engineering team, freed from firefighting, shipped 14 new features in the first quarter post-launch — more than the previous four quarters combined.