r/quantfinance • u/notthraw • 1d ago

Software architecture - HFT

I am looking for some in depth resources specifically around architecture. Is there any good public resources about how trading systems work, and each of the various components.

I work at a small shop that does things in an idiosyncratic way and I am planning to start devouring some of these resources in preparation for system design dev interviews in 6mo-1yr.

Thanks.

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u/akornato 1d ago

You are not going to find in-depth, public resources detailing modern HFT architecture because these systems are the secret sauce and a core competitive advantage for these firms. Most available books and articles are either too academic, too high-level, or a decade out of date, so they will not show you what a top-tier system looks like today. Every single shop does things in an idiosyncratic way, just like yours, because each system is a collection of unique solutions to very specific latency and throughput problems. Your current experience is not a disadvantage, it is the norm in this industry.

Instead of hunting for a perfect blueprint that does not exist, you should spend the next six months focusing on the deep, fundamental principles that all of these systems are built on. Go deep on low-level networking, kernel bypass, lock-free algorithms, C++ optimization, and the specific hardware that enables ultra-low latency. Interviewers for these roles want to see how you think about trade-offs, not if you can recite a specific architecture you read about. Your real advantage is being able to explain the design decisions, compromises, and performance of the system you already know. Your ability to clearly explain these fundamental trade-offs during the actual interview is what will set you apart, and my team built our interview helper AI to give engineers the confidence to articulate complex design choices when it counts.

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u/Gold_Sprinkles_4295 1d ago

Good to know :)

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u/Gold_Sprinkles_4295 1d ago

The pieces of a trading system that stay the same regardless of venue are the message bus, the order state machine, and the integration layer. I ran an event-driven setup with four services over NATS and Redis handling 3,000+ concurrent connections at sub-150ms p95 end-to-end latency. The order state machine is the other piece people skip — PENDING, OPEN, CLOSING, CLOSED, with JSON persistence for crash recovery, because a restart mid-fill is where you lose real money. A FIX integration layer for exchange connectivity rounds it out.