Principal Software Engineer
Principal Engineer
London | Hybrid | Permanent
Salary: Up to £140,000 + Bonus & Benefits
Harrington Starr is partnering with a leading financial technology firm to hire a Principal C# Software Engineer based in London.
This is a senior technical leadership role focused on real-time trading technology, platform modernisation and re-architecture, combining hands-on engineering, architecture and mentoring.
The Role:
- Shape the technical roadmap and platform re-architecture strategy
- Design and evolve low-latency, event-driven distributed systems
- Lead platform development through to production and improve scalability, resilience and performance
- Drive improvements across automation, observability, CI/CD and developer productivity
- Partner with Engineering, Product and Operations to deliver practical technical solutions
- Mentor engineers and champion engineering standards, best practices and continuous improvement
What We're Looking For:
- Strong C#/.NET software engineering experience
- Proven experience building scalable, high-performance distributed systems
- Strong understanding of real-time and low-latency architecture
- Experience leading modernisation, migration or re-architecture programmes
- Experience with cloud-native architectures, APIs, event-driven systems and CI/CD
- Financial markets experience, ideally across electronic trading, OTC derivatives, fixed income, FX or similar, with strong technical leadership skills
Benefits:
- Up to £140,000 base salary + discretionary bonus
- 25 days annual leave + bank holidays
- Hybrid and flexible working
- Private Medical Insurance and Life Insurance
- Pension and Employee Assistance Programme
If you’re a Principal-level C# engineer looking to shape architecture, modernise complex platforms and work on real-time financial technology, we’d love to hear from you.