This range is provided by Harrington Starr. Your actual pay will be based on your skills and experience — talk with your recruiter to learn more.

Base pay range

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Associate Vice President @ Harrington Starr

Senior Software Engineer

London, UK

We’re looking for a Senior Performance Software Engineer to take ownership of optimising large-scale, high-performance systems used by demanding clients worldwide. You’ll work across the full delivery lifecycle, from profiling and tuning code, to rethinking architectures ensuring software runs with maximum speed, minimal memory usage, and rock-solid scalability.

This is a hands on role where you’ll dive deep into complex systems, identify bottlenecks, and implement improvements that make a measurable difference for clients.

What you’ll be doing

• Profiling and optimising existing code to boost performance and reduce memory footprint
• Designing and implementing performance enhancements for high-throughput, low-latency systems
• Working with Product, Engineering, and Clients to understand and meet performance targets
• Creating and maintaining automated performance and load testing frameworks
• Mentoring engineers on writing efficient, scalable, and maintainable code
• Contributing to architectural decisions that directly impact performance and reliability

What we’re looking for

• Senior level experience in software engineering with strong experience in Python, Java, or C#
• Proven track record of performance tuning in large-scale, distributed systems
• Expertise in profiling tools, memory management, and debugging complex performance issues
• Strong database optimisation skills (Postgres, SQL Server, or similar)
• Experience with containerised and cloud-native environments (Kubernetes, Docker, AWS, Azure)
• Familiarity with load testing tools (e.g. k6, JMeter, Gatling) and monitoring solutions
• Excellent communication skills to work with both technical and non-technical stakeholders

What’s on offer

• Collaborative environment where technical excellence and innovation are valued
• Projects that make a visible impact on system speed, efficiency, and scalability
• The opportunity to shape system architecture and mentor future engineering leaders
• Flexible Hybrid working in Central London
• up to £140,000 basic plus market leading bonus structures

If you’re passionate about pushing the boundaries of performance engineering and building software that scales effortlessly, we’d love to hear from you.

Seniority level

• Seniority level

  Mid-Senior level

Employment type

• Employment type

  Full-time

Job function

• Job function

  Information Technology

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