Execution algorithms, transaction cost analysis, and the risk layer around them. The problem is narrow and testable: take a large order, work it into the market without moving it, and prove afterwards exactly what it cost.
These three are usually separate tools that never quite agree with each other. I build them against a single event stream, so they always do.
Working a parent order into the market without moving it — adapting to the liquidity that's actually there rather than following a fixed schedule.
What the execution actually cost, broken into its parts rather than averaged into a single flattering number. Decomposed, so each part can be argued with.
Limits checked before an order reaches the venue rather than reconciled after it. A kill switch that stops the system instead of politely asking it to.
Most trading failures aren't bad strategies. They're systems that behaved differently in production than in research, or that couldn't say afterwards what they had done. These three remove those failures by construction rather than by vigilance.
Algorithms consume the same events whether they come from a historical file or a live venue, and cannot tell which. If code branches on "am I backtesting", that's a design bug. Divergence becomes structurally impossible rather than something to hunt for.
Every order, fill and decision is written down before it is acted on. Any day can be replayed and any millisecond accounted for. That's the difference between a performance claim and an auditable one.
The system is designed to be killed mid-order. On restart it reads its log, queries the venue, reconciles the difference and resumes — without duplicating an order or losing a position.
Chosen for correctness under failure rather than for novelty.
I'm a quantitative developer working on execution and market microstructure. I came to it from the trading side rather than from software, which is why I care less about elegant abstractions and more about whether a system can tell you honestly what it did at 3am on a bad day.
Most of my time goes into qexec — an execution management system built on NautilusTrader, running against Binance spot and perpetuals. Everything on this page is drawn from that work.
If you're working on execution, measurement, or trading infrastructure — or want an existing setup reviewed honestly — I'm glad to talk. Tell me what you're trading and I'll tell you straight whether I can help.