Senior Software Engineer

Job Description

Software Engineer (Senior) - C#/.Net & SQL Server | Trading Desk Engineering | Hedge Fund

• London (primarily office based in Liverpool Street)
• Permanent, Full-time
• £120,000 – £160,000 base + discretionary bonus (of up to 100%)

The role:

This is an opportunity to join a systematic trading firm as a Senior Software Engineer working directly with the trading desk on the platform that executes trades in live markets.

You will be based in the firm’s Liverpool Street front-office trading floor working alongside the traders, senior engineers and the CEO. The firm has around 18 employees, with roughly 9 engineers today (growing to 10). Technology sits at the centre of the business, and engineers work directly on the systems that power trading activity.

The environment is fast-paced and trading desk focused, meaning you will regularly context switch between development work and real-time trading needs. You will work closely with end users and have direct access to senior leadership, especially the CEO, so strong communication, attention to detail and empathy for users is important. The role focuses on evolving an established platform while contributing to the longer-term modernisation of the architecture.

Non-Negotiables:

• Strong software engineering experience (C# preferred but Java, or C++ considered)
• Strong SQL / relational database experience
• Careful approach to testing and safe refactoring
• Clear, concise technical and verbal communication
• Have previously worked for a Financial Service organisation or for a software vendor that’s utilised within the Financial Service industry.

What You’ll Work With

• C#
• .NET Framework
• SQL Server
• WinForms desktop applications
• Azure infrastructure
• Legacy platform modernisation
• Automated testing
• Kafka

Future platform direction includes:

• Docker / containerisation
• Modernised execution architecture

Core Responsibilities:

• Maintain and improve the trading execution platform
• Refactor and enhance a long-lived C#/.NET application
• Make safe changes to legacy code while preserving behaviour
• Write tests that validate and document system behaviour
• Deliver small, well-structured changes with clear commits
• Work with traders to support real-time trading needs
• Improve system usability and operational efficiency
• Contribute to the future rebuild of the execution platform
• Collaborate with engineers across trading systems and infrastructure

Examples of the kinds of changes you’ll make to the application:

• Incremental changes, tweaks and improvements across the execution platform
• Adding new features that support trading workflows and strategies
• Cleaning up parts of the UI to improve usability
• Simplifying the platform so junior engineers can build starter algorithms without relying on senior leadership for every change

Nice to Haves

• Exposure to futures, options, or crypto markets
• Experience improving legacy or difficult-to-test systems
• Experience refactoring large codebases
• Exposure to Python or DevOps tooling
• Experience in smaller, high-ownership engineering teams

Why Join

You will join a small, engineering-led systematic trading firm where software sits at the core of the business. Around half the company is technical, and engineers work directly on the systems that drive trading performance.

The trading desk engineering role offers unusually close collaboration with traders and senior technical leadership, giving you real insight and influence over how the platform evolves.

Software Engineer (Senior) - C#/.Net & SQL Server | Trading Desk Engineering | Hedge Fund