Senior Software Engineer – Ultra Low Latency Risk Engine Developer (VP)

Citigroup Inc.; Belfast City District; Hybrid; GBP 110,000 - 150,000; Full time

Benefits offered by this job

27 days annual leave

Discretional bonus

Private Medical Care

Job summary

Citigroup Inc. in the United Kingdom is hiring a Senior Software Engineer to build and maintain an ultra low-latency risk engine for cash equities trading. You will own latency-sensitive components in the risk path, drive architecture decisions, and collaborate with global teams across APAC/EMEA/NAM while mentoring junior engineers.

The role offers a hybrid work model, competitive base salary, and a broad benefits package aimed at supporting professional growth and work-life balance.

Qualifications

• Proven software engineering experience building latency-critical systems for financial trading.
• Strong expertise in low-latency Java and/or C++ with multi-threading and concurrency.
• Experience with high-throughput messaging and IPC frameworks.

Responsibilities

• Design, develop, and maintain ultra low-latency risk engine for real-time checks.
• Architect and optimize multi-threaded components with sub-microsecond performance.
• Coordinate delivery across global teams and mentor engineers.

Skills

Low Latency Java / C++

Multithreading

Java NIO

GC tuning

C++ performance

Linux tuning

Real-time risk management

Education

Bachelor's degree in CS/Engineering

Master's degree preferred

Tools

Aeron

Solace

Job description

Discover your future at Citi

Working at Citi is far more than just a job. A career with us means joining a team of more than 230,000 dedicated people from around the globe. At Citi, you’ll have the opportunity to grow your career, give back to your community and make a real impact.

Job Overview

Engineer the future of global finance. At Citi, our Tech team doesn’t just support finance – we are helping to redefine it. Every day, $5 trillion crosses through our network. We do business in 180+ countries operating at a scale few can match. From deploying advanced AI to helping shape global markets, we build systems that matter. Look to join a team where your work helps influence economies, your ideas can drive innovation and outcomes, and your growth is backed by mentorship, continuous learning and flexibility with potential hybrid work opportunities. Help solve real-world challenges that touch millions and get the opportunity to build the future of finance with Citi Tech.

Citi's Equities Technology organization is seeking a Senior Software Engineer – Ultra Low Latency Risk Engine Developer to join the Equities Electronic Execution (Electronic Trading) technology team. This role is focused on the design, development, and delivery of Citi's next-generation low-latency Risk Engine for cash equities and its integration into the broader execution platform — encompassing the Centralised Position Service, Client Connectivity, Market Access layers, and high-throughput market data processing.

The engineer will own critical, latency-sensitive risk-checking components that sit directly in the cash equities trading hot path, ensuring pre-trade and real-time risk controls are enforced with microsecond-level performance while maintaining correctness and resiliency at scale. This is a hands-on, deeply technical role that also carries leadership responsibilities — mentoring engineers, driving architecture decisions, and coordinating delivery across global development centers.

The person will collaborate closely with product development, quantitative research, technology infrastructure, production support, and QA teams, with close alignment to global strategy and cross-regional delivery (APAC, EMEA, NAM).

Responsibilities:

• Partner with multiple management teams to ensure appropriate integration of functions to meet goals as well as identify and define necessary system enhancements to deploy new products and process improvements
• Resolve variety of high impact problems/projects through in-depth evaluation of complex business processes, system processes, and industry standards
• Provide expertise in area and advanced knowledge of applications programming and ensure application design adheres to the overall architecture blueprint
• Utilize advanced knowledge of system flow and develop standards for coding, testing, debugging, and implementation
• Develop comprehensive knowledge of how areas of business, such as architecture and infrastructure, integrate to accomplish business goals
• Provide in-depth analysis with interpretive thinking to define issues and develop innovative solutions
• Serve as advisor or coach to mid-level developers and analysts, allocating work as necessary
• Appropriately assess risk when business decisions are made, demonstrating particular consideration for the firm's reputation and safeguarding Citigroup, its clients and assets, by driving compliance with applicable laws, rules and regulations, adhering to Policy, applying sound ethical judgment regarding personal behavior, conduct and business practices, and escalating, managing and reporting control issues with transparency.

Risk Engine & Core Development

• Design, develop, and maintain the ultra low-latency, in-line Risk Engine responsible for real-time pre-trade risk checks, position limits, and exposure controls across cash equities electronic execution flows.
• Architect and optimize high-performance, lock-minimal, multi-threaded components capable of processing risk decisions in the sub-microsecond to low-microsecond range.
• Integrate risk and position components with Client Connectivity, Market Access layers, and high-throughput market data feed handlers.
• Apply deep expertise in JVM performance tuning, memory management, garbage collection avoidance, and/or native (C++/Rust) performance engineering to eliminate latency outliers ("jitter") in the risk path.
• Perform system-level performance tuning to minimize end-to-end latency and jitter across the risk and execution path.

Recommended Qualifications:

• Proven software engineering experience, with substantial hands‑on experience building risk management, position-keeping, or other latency-critical systems for cash equities electronic trading or algorithmic trading platforms at a global investment bank or equivalent financial institution.
• Strong, hands‑on technical expertise in Low Latency Java and/or C++ (Rust a plus), including multi-threading, concurrency, lock-free data structures, Java NIO, and JVM/GC performance tuning.
• Hands‑on experience with low‑latency messaging and IPC frameworks such as Aeron, Solace, or equivalent shared-memory/IPC technologies for building distributed, high-throughput trading systems.
• Demonstrated background in real-time distributed risk management systems for cash equities flow products, including asynchronous, event-driven architectures.
• Practical, hands‑on experience with NUMA-aware design, CPU core pinning/affinity and isolation, Linux kernel/OS tuning, and low-latency networking (kernel bypass, RDMA, or specialized NIC tuning) for ultra low-latency, high-throughput systems.
• Strong understanding of automated testing techniques, test-driven development, and quality engineering practices for mission-critical systems.
• Excellent communication skills, with the ability to present and grasp complex technical and risk concepts in a multicultural, cross-regional environment, and to work effectively with globally distributed stakeholders (trading desks, quants, infrastructure, and support teams).
• Working knowledge of regional exchange microstructure and relevant regulatory regimes governing cash equities electronic trading and risk controls.

Education:

• Bachelor’s degree/University degree or equivalent experience
• Master’s degree preferred

This job description provides a high-level review of the types of work performed. Other job-related duties may be assigned as required.

What we’ll provide you

By joining Citi, you will not only be part of a business casual workplace with a hybrid working model (up to 2 days working at home per week), but also receive a competitive base salary (which is annually reviewed), and enjoy a whole host of additional benefits such as:

27 days annual leave (plus bank holidays)

A discretional annual performance related bonus

Private Medical Care & Life Insurance

Employee Assistance Program

Pension Plan

Paid Parental Leave

Special discounts for employees, family, and friends

Access to an array of learning and development resources

Visit ourGlobal Benefitspage to learn more.

Alongside these benefits Citi is committed to ensuring our workplace is where everyone feels comfortable coming to work as their whole self, every day. We want the best talent around the world to be energized to join us, motivated to stay and empowered to thrive.

#LI-MR7

Job Family Group:

Technology

Job Family:

Applications Development

Time Type:

Full time

Most Relevant Skills

Please see the requirements listed above.

Other Relevant Skills

For complementary skills, please see above and/or contact the recruiter.

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