Software Engineer, Trading Systems

About Posley (https://posleyim.com) Posley is a quantitative investment firm focused on opportunities across traditional and alternative markets. We study how price, funding, liquidity, market structure and execution interact across markets, and build systematic trading strategies around those opportunities. We combine the discipline of a licensed investment environment with the speed and ownership of a startup. Our core research, trading and technology capabilities are built in-house, so engineers work closely with researchers and traders and see their systems running in live markets. The Role We are looking for a strong software engineer to help build and improve our trading and execution infrastructure. This is not a pure DevOps role and not a traditional backend role. You will work on systems that directly interact with live markets — including execution engines, exchange connectivity, position and order management, monitoring, reconciliation and production infrastructure. You should be someone who cares about correctness, edge cases and details, while having enough trading intuition to understand why those details matter. What You Will Work On Develop exchange connectivity through WebSocket / REST APIsImprove order, position and account state managementHandle execution edge cases, failures, retries and reconciliationBuild monitoring and safeguards for live trading systemsImprove latency, reliability and operational resilienceInvestigate discrepancies in positions, balances, fills, fees and P&LSupport deployment, cloud infrastructure and DevOps where neededWork directly with quantitative researchers to bring strategies into productionBecause we are a startup, the scope will evolve. If something important sits between research, trading and infrastructure, you may end up owning it. What We Are Looking For Strong software engineering fundamentalsExperience building reliable backend or distributed systemsStrong attention to detail and a high standard for correctnessAble to reason about asynchronous systems, state and failure scenariosComfortable taking ownership without needing detailed instructionsGenuine interest in trading, markets or quantitative systemsAble to use AI coding agents effectively while critically reviewing and validating production-critical codeYou do not need to be a quantitative researcher, but you should have enough numerical and market intuition to understand concepts such as: orders, fills and positionsbid / ask and liquidityexposure and P&Lfees and fundinglatency and execution qualitybasic risk controls Technology Skills Our systems primarily use: Python for trading, execution, research and analyticsTypeScript / Node.js across selected infrastructure and internal systemsAWS / Linux / DockerRedis and messaging / streaming infrastructureTime-series databases and monitoring systemsAPIs across centralized and decentralized trading venuesExperience with every technology above is not required. Strong engineering ability matters more than matching the stack exactly. Nice to Have Experience with trading systems, exchanges or market dataCrypto exchange API experienceLow-latency or high-throughput systemsAWS / Linux / Docker production experienceExperience with reconciliation or financial systemsUnderstanding of market microstructurePersonal interest in systematic or algorithmic trading Why Posley You will not be maintaining one small component inside a large engineering organisation. You will have the opportunity to: work within a licensed quantitative investment environmentbuild systems used directly in live tradinggain exposure to both traditional and virtual asset marketsown meaningful pieces of production infrastructurework closely with traders and quantitative researcherssee the impact of your engineering decisions quicklysolve problems across software, markets and infrastructure We value people who are curious, rigorous, hands-on and serious about getting the details right. If you enjoy building systems where small engineering details can have real financial consequences, we would like to hear from you.