Senior Software Developer

Spectrum IT Recruitment; City Of London; On-site; GBP 70,000 - 110,000; Full time

Job summary

Spectrum IT Recruitment is seeking an experienced Senior Software Developer in central London to join a technically focused engineering team supporting trading strategies and quantitative research. You will own major development work, influence architectural direction and collaborate with traders and researchers on high-performance systems.

The role emphasizes low-latency, multithreaded programming, robust SQL and cross-team collaboration, with a clear path to shaping engineering standards and

Qualifications

• At least five years' commercial software development experience with C#/.NET.
• Proficient in object-oriented design, software architecture and design principles.
• Experience delivering production applications with emphasis on performance, reliability and scalability.
• Strong SQL skills and relational database experience.
• Familiar with full software development lifecycle.
• Analytical mindset and problem solving.
• Excellent communication with technical and non-technical stakeholders.
• Degree in a technical discipline.
• Experience with low-latency, high-throughput, multithreaded or parallel systems.
• Networking experience using TCP/IP or UDP.
• Knowledge of distributed systems and service-oriented architectures.
• Experience with performance profiling and optimization.
• Interest in financial markets, algorithmic trading or quantitative research.
• Experience collaborating with quantitative researchers and traders.

Responsibilities

• Design and develop high-performance applications using C# and modern .NET.
• Own complex projects from initial requirements and technical design through to production.
• Shape architecture and contribute to key technical decisions.
• Build scalable systems supporting trading, research and data-intensive applications.
• Develop and optimise relational database solutions using SQL Server, Oracle or similar.
• Investigate performance bottlenecks and improve application and database efficiency.
• Apply multithreading, concurrency and asynchronous programming to demanding problems.
• Strengthen software quality through code reviews, automated testing and CI.
• Mentor other developers and help maintain high engineering standards.

Skills

C# / .NET

OOP

SQL

Multithreading

Distributed systems

TCP/IP UDP

Architecture

CI/CD

Unit testing

Mentoring

Communication

Education

Bachelor's degree in Computer Science, Mathematics, Physics, Engineering, or a related technical discipline

Tools

None

Job description

We're looking for an experienced Senior Software Developer to join a highly technical engineering team developing systems that directly support trading strategies, automated trading, and quantitative research.

This opportunity suits a strong C#/.NET engineer who enjoys complex technical challenges, performance-critical development and influencing how software is designed and built. Working across greenfield projects and established platforms, you'll take ownership of significant development work and help shape architecture, technical direction, and engineering standards. You'll collaborate closely with quantitative researchers, traders, and experienced engineers, translating complex requirements into reliable, scalable software.
This is a full-time office based role in central London.

The Role:

• Design and develop high-performance applications using C# and modern .NET.
• Own complex projects from initial requirements and technical design through to production.
• Shape architecture and contribute to key technical decisions.
• Build scalable systems supporting trading, research and data-intensive applications.
• Develop and optimise relational database solutions using SQL Server, Oracle or similar technologies.
• Investigate performance bottlenecks and improve application and database efficiency.
• Apply multithreading, concurrency and asynchronous programming to demanding engineering problems.
• Strengthen software quality through code reviews, automated testing and continuous integration.
• Mentor other developers and help maintain high engineering standards.
  

Skills Required:

• At least five years' commercial software development experience, with strong expertise in C# and modern .NET.
• Excellent understanding of object-oriented programming, software design principles and architecture.
• Experience delivering production applications where performance, reliability and scalability are essential.
• Strong SQL skills and experience with relational databases.
• A thorough understanding of the full software development lifecycle.
• Strong analytical skills and a practical approach to solving complex problems.
• Clear communication skills and the ability to work effectively with technical and non-technical colleagues.
• A degree in Computer Science, Mathematics, Physics, Engineering, or a related technical discipline.
  
• Low-latency, high-throughput, multithreaded or parallel systems.
• Network programming using TCP/IP or UDP.
• Distributed systems and service-oriented architectures.
• Performance profiling and optimisation.
• Financial markets, algorithmic trading or quantitative research.
• Working directly with quantitative analysts, researchers, traders or data scientists.
  

Why Apply?

This is an opportunity to take on technically demanding work with a direct connection to trading and research. You'll have meaningful ownership, influence over engineering decisions and the chance to build high-performance software alongside colleagues with deep technical and quantitative expertise.

If you're an experienced C#/.NET developer looking for technical depth and the opportunity to shape complex systems, we'd like to hear from you.