Software Engineer

Marlin Selection Ltd; Greater London; Hybrid; GBP 80,000 - 100,000; Full time

Job summary

A financial trading firm in London is seeking an experienced Software Engineer to enhance and support their in-house trading systems. You will engage directly with stakeholders in a fast-paced environment, contributing to software development and production support. The ideal candidate has over 5 years of experience in C#/.NET and is comfortable working in high-pressure situations. This role offers competitive compensation, flexible working arrangements, and direct exposure to live trading systems.

Benefits

Competitive compensation package

Flexible working arrangements

Direct exposure to live trading systems

Qualifications

• 5+ years’ software development experience in C# and .NET.
• Strong SQL Server and database design knowledge.
• Experience in financial services or trading environments.

Responsibilities

• Design and maintain trading systems.
• Contribute to daily development in C#/.NET.
• Support architectural decisions and technical roadmap.

Skills

C#

.NET

SQL Server

Analytical skills

Problem-solving

Message brokers

Software development experience

Tools

Microsoft SQL Server

RabbitMQ

FIX engine

Excel VBA

Job description

Location: London (City) – Hybrid / On-site / Remote

We are a London-based financial trading firm seeking an experienced Software Engineer to join our development team and support the ongoing evolution of our in-house trading and brokerage systems.

This is a hands‑on, business‑critical role within a fast‑paced trading environment. You will work directly with the Head of Development and collaborate closely with trading, operations, and infrastructure teams to maintain and enhance a proprietary platform used daily across Europe, the US, and Asia.

The Opportunity

You will play a key role in developing, supporting, and modernising core trading systems covering trade booking, P&L and risk capture, confirmations, reporting, and messaging integrations.

This role combines active software development with live production support and direct engagement with front‑office stakeholders.

Key Responsibilities

Design, develop, and maintain in‑house trading and booking systems

Contribute hands‑on to daily development in C# / .NET

Review and improve code quality, performance, and security

Support architectural decisions and technical roadmap initiatives

Enhance system stability, scalability, and resilience

Assist in modernising legacy applications, including migration initiatives

Provide support within live trading environments

Diagnose and resolve complex technical and business‑critical issues

Translate business requirements into effective technical solutions

Coordinate with Infrastructure and IT Support teams

Technical Environment

• C#
• Microsoft SQL Server
• In‑house FIX engine
• Excel VBA‑based systems
• Fully in‑house developed platform

Skills & Experience

• 5+ years’ professional software development experience
• Strong expertise in C# and .NET (modern .NET advantageous)
• Experience maintaining and enhancing legacy systems
• Solid SQL Server and database design knowledge
• Experience with message brokers (e.g., RabbitMQ)
• Understanding of distributed systems
• Experience within financial services, brokerage, or trading environments
• Knowledge of equity and/or derivatives trading workflows
• Strong analytical and problem‑solving skills
• Ability to operate effectively in high‑pressure, business‑critical environments

Highly Desirable

• Trading platform or booking system experience
• FIX protocol knowledge
• VBA experience
• Experience migrating WinForms applications to modern architectures
• Azure cloud architecture exposure
• CI/CD and automation experience

Profile

We are looking for a motivated, commercially aware engineer who is:

Comfortable working with responsibility and autonomy

A strong communicator across technical and non‑technical teams

Pragmatic and solution‑focused

Willing to take ownership and contribute beyond defined responsibilities

What We Offer

High‑impact role within a growing financial firm

Direct exposure to live trading systems

Competitive compensation package

Flexible working arrangements

Opportunity to contribute to the long‑term evolution of a proprietary trading platform

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Contacts

UK & Europe: [phone]
Middle East + Asia: [phone]