Lead Software Developer C# – Trading Systems
Location: London (City) – Hybrid / Remote Options
Our client is a growing global financial trading firm seeking a senior, hands-on Software Engineer to take ownership of our in-house trading and brokerage platforms.
This is a high-impact leadership role reporting directly to the CEO/COO, offering direct exposure to executive management and genuine influence over long-term technology strategy.
You will assume responsibility for a mission-critical trading system used daily across Europe, the US and Asia, playing a central role in stabilising, enhancing and modernising our core infrastructure.
The Role
This position combines:
1. Hands-on development (C# / .NET)
2. System architecture ownership
3. Team leadership
4. Business-facing engagement with traders and senior stakeholders
You will lead the technical roadmap of our trading and booking platforms while ensuring resilience, scalability and operational stability in a live trading environment.
Key Responsibilities
5. Lead development and architectural direction of in-house trading systems
6. Contribute hands-on to coding and system enhancement
7. Oversee trade booking, lifecycle management, P&L and risk capture systems
8. Support messaging, integrations and reporting infrastructure
9. Provide senior-level production support in live trading environments
10. Manage and mentor a small development team (with planned growth)
11. Reduce key-person dependency through documentation and knowledge transfer
12. Drive modernisation initiatives, including migration from legacy technologies
13. Partner closely with trading teams and senior management
Technical Environment
14. C#
15. .NET Framework 4.7.2 (WinForms)
16. Microsoft SQL Server
17. RabbitMQ
18. In-house FIX engine
19. Microsoft Azure
20. Azure DevOps
21. Excel VBA-based tools
22. Fully in-house developed systems
Experience Required
Essential:
23. 7–10+ years software development experience
24. Strong C# and .NET expertise
25. Experience maintaining and evolving legacy systems
26. Solid SQL Server and database design knowledge
27. Experience within trading, brokerage or financial services environments
28. Understanding of equity and/or derivatives trading workflows
29. Experience leading technical teams
30. Strong problem-solving capability in high-pressure environments
Highly Desirable:
31. Trading platform or booking system experience
32. FIX protocol knowledge
33. Experience migrating WinForms to modern architectures
34. Azure cloud architecture experience
35. CI/CD and automation exposure
Profile
We are looking for someone who is:
36. Commercially minded and pragmatic
37. Comfortable operating with autonomy and high responsibility
38. Able to balance production support with long-term strategic improvement
39. Confident communicating with both technical and non-technical stakeholders
40. Motivated to build sustainable, long-term system ownership
What We Offer
41. Senior leadership position in a growing financial firm
42. Direct reporting line to executive management
43. Business-critical remit with genuine impact
44. Competitive compensation package
45. Flexible working arrangements
46. Opportunity to shape the long-term technology strategy of a global trading platform