Software Engineer, Trading Systems

Posley Company Limited; Hong Kong Island; On-site; HKD 600,000 - 900,000; Full time

Job summary

Posley Company Limited 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 are seeking a strong software engineer to help build and improve our trading and execution infrastructure. You will work on live-market systems including execution engines, exchange connectivity, position and

Qualifications

• Strong software engineering fundamentals.
• Experience building reliable backend or distributed systems.
• Strong attention to detail and a high standard for correctness.
• Able to reason about asynchronous systems, state and failure scenarios.
• Comfortable taking ownership without needing detailed instructions.
• Genuine interest in trading, markets or quantitative systems.
• Able to use AI coding agents effectively while critically reviewing and validating production-critical code.

Responsibilities

• Develop exchange connectivity through WebSocket / REST APIs.
• Improve order, position and account state management.
• Handle execution edge cases, failures, retries and reconciliation.
• Build monitoring and safeguards for live trading systems.
• Improve latency, reliability and operational resilience.
• Investigate discrepancies in positions, balances, fills, fees and P&L.
• Support deployment, cloud infrastructure and DevOps where needed.
• Work directly with quantitative researchers to bring strategies into production.
• Scope evolves; own between research, trading and infrastructure.

Skills

Python

TypeScript / Node.js

Distributed systems

Backend development

Async programming

Ownership

Trading/markets interest

Tools

Redis

Time-series databases

APIs

Messaging/Streaming

Job description

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 APIs

Improve order, position and account state management

Handle execution edge cases, failures, retries and reconciliation

Build monitoring and safeguards for live trading systems

Improve latency, reliability and operational resilience

Investigate discrepancies in positions, balances, fills, fees and P&L

Support deployment, cloud infrastructure and DevOps where needed

Work directly with quantitative researchers to bring strategies into production

Because 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 fundamentals

Experience building reliable backend or distributed systems

Strong attention to detail and a high standard for correctness

Able to reason about asynchronous systems, state and failure scenarios

Comfortable taking ownership without needing detailed instructions

Genuine interest in trading, markets or quantitative systems

Able to use AI coding agents effectively while critically reviewing and validating production-critical code

You 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 positions

bid / ask and liquidity

exposure and P&L

fees and funding

latency and execution quality

basic risk controls

Technical Skills

Our systems primarily use:

Python for trading, execution, research and analytics

TypeScript / Node.js across selected infrastructure and internal systems

Redis and messaging / streaming infrastructure

Time-series databases and monitoring systems

APIs across centralized and decentralized trading venues

Experience 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 data

Low-latency or high-throughput systems

Experience with reconciliation or financial systems

Understanding of market microstructure

Personal 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 environment

build systems used directly in live trading

gain exposure to both traditional and virtual asset markets

own meaningful pieces of production infrastructure

work closely with traders and quantitative researchers

see the impact of your engineering decisions quickly

solve 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.