Principal Software Engineer - C#

TP ICAP; City Of London; Hybrid; GBP 120,000 - 180,000; Full time

Job summary

TP ICAP is seeking a Principal Engineer to own architecture, design, and hands-on delivery for a desktop trading platform. The role combines technical leadership with hands-on coding to streamline trading desk workflows and guide a greenfield project through production operations.

You will apply deep technical expertise, partner with offshore teams, and establish AI-assisted development practices while maintaining strict security and governance standards.

Qualifications

• 10+ years in Financial Services building complex front-office trading systems.
• Demonstrated success leading engineering teams through multi-year transformation programmes.
• Hands-on experience across the full software development lifecycle.
• Practical experience using AI tools across the development lifecycle, including AI-generated code review.
• Excellent written and verbal communication; effective in a matrixed, global organisation.

Responsibilities

• Architect the platform, write correctness-critical code, and set engineering bar by your own output.
• Own the technical direction of the ICRV greenfield project, delivering high-performance, scalable solutions from design to production.
• Design for latency budgets, crash containment, and least-privilege isolation between sub-applications.
• Mentor and coach team members and coordinate with offshore staffing vendors.
• Establish AI-assisted development as a disciplined practice with vetted tooling and safe code review.

Skills

C# / .NET

React

TypeScript

WebSocket

AI-assisted development

Leadership

Communication

Education

Degree in Computer Science, Engineering, Mathematics, Physics, or a relevant analytical discipline

Tools

Electron

OpenFin

Bloomberg DAPI

WPF

AWS / Cloud

Job description

The TP ICAP Group is a world leading provider of market infrastructure.Our purpose is to provide clients with access to global financial and commodities markets, improving price discovery, liquidity, and distribution of data, through responsible and innovative solutions.Through our people and technology, we connect clients to superior liquidity and data solutions.The Group is home to a stable of premium brands. Collectively, TP ICAP is the largest interdealer broker in the world by revenue, the number one Energy & Commodities broker in the world, the world’s leading provider of OTC data, and an award winning all-to-all trading platform.Founded in London in 1866, the Group operates from more than 60 offices in 27 countries. We are 5,200 people strong. We work as one to achieve our vision of being the world’s most trusted, innovative, liquidity and data solutions specialist.About ICAP RVICAP Relative Value (ICRV) is a dedicated global execution division specializing in US Treasuries (USTs), Futures, and Options markets. Operating around the clock, the unit consists of a dedicated team that executes complex, multi-leg synthetic strategies on behalf of institutional clients.Role OverviewICRV are seeking an exceptional Principal Engineer to own the architecture, design and hands-on delivery of desktop platform automating and streamlining trading desk workflows. This is a high-visibility player-coach role: you will apply deep technical expertise with architectural leadership, to transform desk operations and have a significant influence on the technology direction of this new platform working with offshore partners. It may evolve to include formal people management.Role ResponsibilitiesAct as the primary hands-on technical leader: architect the platform, write correctness-critical code, and set the engineering bar through your own output.Own the technical direction of the ICRV greenfield project, developing high-performance, scalable, and robust solutions from first principles through to production operation.Design for hard non-functional requirements: latency and responsiveness budgets as acceptance criteria, crash containment, least-privilege isolation between sub-applications.Work effectively with a matrix management structure, taking designs through group-wide governance, while delivering business value ensuring adherence to group wide technology standards and mandates.Mentor and coach other team members to achieve optimum performance and career growth. Work effectively to leverage offshore staffing vendors.Establish AI-assisted development as a disciplined team practice using company wide tooling, workflow integration, and the review rigour that makes AI-generated code safe to ship.Communicate technical trade-offs clearly to trading, compliance, infrastructure and middle-office stakeholders; manage risk and escalate honestly.Identify and drive refactoring toward the target architecture as the platform grows.Experience / CompetencesEssentialExperience:10+ years Financial Services building complex front-office trading systems, with demonstrated technical leadership through multi-year delivery.Demonstrated success leading engineering teams through complex, multi-year transformation programmes.Hands-on experience across the full software development lifecycle.Practical experience using AI tools across the development lifecycle, including the review discipline for AI-generated code.Excellent written and verbal communication; effective in a matrixed, global organisation; self-motivated and proactive.Degree in Computer Science, Engineering, Mathematics, Physics, or a relevant analytical discipline.Domain:Understanding of relative-value execution: cash/futures basis, calendar spreads, curve trades, and how that translates into workflow and system requirements.Familiarity with futures market structure (exchange, clearing, margining) and US Treasury market structure (cash bonds, primary dealers, settlement).Knowledge of futures clearing/margin systems (e.g. CME) and Treasury settlement railsExperience with execution/order connectivity protocols (FIX or equivalent) in an interdealer, agency, or execution-desk context.Understanding of 24-hour, multi-region trading operations (follow-the-sun handover, timezone-aware processing across London/New York/Singapore)Technical:Expert-level C# / .NET (LTS): back-end services with ASP.NET Core.Experience designing and delivering event-driven, service-oriented back-end systems (message brokers, async workflows, API design) in a production trading environment.Experience building desktop applications that host web content (e.g., Electron, Tauri, or custom .NET host); comfortable with WebSocket bridges, local service APIs, or IPC mechanisms to connect web UIs with native desktop applications.Sufficient front-end literacy (React, TypeScript, Node) to make architectural decisions, review code, and collaborate effectively with dedicated front-end teams.Demonstrated ability to leverage coding agents in spec-driven development workflows.Strong grasp of process isolation, information security, and identity/access management; experience with event-driven messaging and least-privilege service boundaries.Familiarity with modern build pipelines and tools.Experience designing within formal governance and architecture-review frameworks.DesiredExperience with desktop interop frameworks and protocols (FDC3, OpenFin, or custom IPC/message-bus implementations).WPF or other rich-client .NET UI experience.Experience interfacing with third-party desktop APIs (e.g., Bloomberg DAPI).Performance engineering: profiling and holding hard latency budgets.Experience with high-throughput trade/market-data processing at scale.Cloud platform experience (AWS or equivalent); containerisation and orchestration.Relational data and canonical/JSON data contract design.Design-system principles and component-library development.Role Band & Level: Manager, 7#LI-Hybrid #LI-DIRNot The Perfect Fit?Concerned that you may not meet the criteria precisely? At TP ICAP, we wholeheartedly believe in fostering inclusivity and cultivating a work environment where everyone can flourish, regardless of your personal or professional background. If you are enthusiastic about this role but find that your experience doesn't align perfectly with every aspect of the job description, we strongly encourage you to apply. You may be the ideal candidate for this position or another opportunity within our organisation. Our dedicated Talent Acquisition team is here to assist you in recognising how your unique skills and abilities can be a valuable contribution. Don't hesitate to take the leap and explore the possibilities. Your potential is what truly matters to us.Company StatementWe know that the best innovation happens when diverse people with different perspectives and skills work together in an inclusive atmosphere. That's why we're building a culture where everyone plays a part in making people feel welcome, ready and willing to contribute. TP ICAP Accord - our Employee Network - is a central to this. As well as representing specific groups, TP ICAP Accord helps increase awareness, collaboration, shares best practice, and holds our firm to account for driving continuous cultural improvement.LocationUK - 135 Bishopsgate - London