Low Latency Trading Infrastructure Engineer

Citi Group; Jacksonville (FL); On-site; USD 170,000 - 260,000; Full time

Job summary

Citi is seeking a Low Latency Trading Infrastructure Engineer in Jacksonville to design and optimize enterprise-grade trading infrastructure. You will architect hardware-accelerated, low-latency systems and integrate them with Citi's secure, scalable platforms used across global markets.

In this role you will operate at the intersection of hardware, networking, and market data, driving nanosecond performance improvements while upholding Citi's standards for reliability and security.

Responsibilities

• Design low-latency topologies: bare-metal servers, NICs, kernel bypass (DPDK/Solarflare), FPGA/co-location hardware.
• Evaluate CPU microarchitecture, NUMA, cache behavior, and memory bandwidth for trading workloads.
• Define hardware/firmware standards with vendors (Dell, HPE, Mellanox/NVIDIA, Arista, Cisco, Juniper).
• Create custom server build patterns for the low-latency trading platform beyond Citi's standard catalog.
• Set standards for low-latency Linux/Windows and microservices, including OS optimizations and CPU isolation.
• Build benchmarking harnesses to measure tick-to-trade latency, jitter, and throughput.
• Tuning: CPU pinning, IRQ affinity, C-state/P-state, huge pages configuration.
• Correlate benchmarks with trading telemetry to validate production readiness.
• Drive packet capture analysis and latency telemetry across the trading stack.
• Architect high-performance colocation environments connecting venues and data feeds.

Job description

About Citi:

Citi, the leading global bank, has approximately 200 million customer accounts and does business in more than 160 countries and jurisdictions. Citi provides consumers, corporations, governments, and institutions with a broad range of financial products and services, including consumer banking and credit, corporate and investment banking, securities brokerage, transaction services, and wealth management.

As a bank with a brain and a soul, Citi creates economic value that is systemically responsible and in our clients' best interests. As a financial institution that touches every region of the world and every sector that shapes your daily life, our Enterprise Operations & Technology teams are charged with a mission that rivals any large tech company. Our technology solutions are the foundations of everything we do from keeping the bank safe, managing global resources, and providing the technical tools our workers need to be successful to designing our digital architecture and ensuring our platforms provide a first-class customer experience. We reimagine client and partner experiences to deliver excellence through secure, reliable, and efficient services.

Our commitment to diversity includes a workforce that represents the clients we serve from all walks of life, backgrounds, and origins. We foster an environment where the best people want to work. We value and demand respect for others, promote individuals based on merit, and ensure opportunities for personal development are widely available to all. Ideal candidates are innovators with well-rounded backgrounds who bring their authentic selves to work and complement our culture of delivering results with pride. If you are a problem solver who seeks passion in your work, come join us. We'll enable growth and progress together.

About the Team:

The Low Latency Trading Infrastructure Engineer is a rare combination of deep technical specialist and mission-critical operator - a professional whose expertise sits at the intersection of hardware engineering, financial markets technology, and performance science. This role sits at the heart of Citi's Global Equity Markets technology organization, responsible for designing, delivering, and sustaining the ultra-low latency infrastructure that powers one of the world's most demanding electronic trading environments. The candidate we seek does not merely maintain infrastructure - they engineer deterministic performance at nanosecond precision, shaping the technical foundation upon which Citi competes in global markets. This is a position for seasoned practitioners who have thrived in high-frequency trading firms, exchange technology groups, or HPC environments, and who bring a rare depth of knowledge spanning bare-metal compute, kernel-bypass networking, FPGA-enabled hardware, and exchange colocation operations.

The successful candidate will operate at the nexus of infrastructure engineering and trading performance, collaborating closely with application development teams, trading desks, risk and compliance stakeholders, and exchange and colocation facility partners. They will drive end-to-end latency optimization across the full trading stack - from BIOS tuning and NIC configuration through to circuit provisioning and market data distribution - while ensuring that every environment meets Citi's stringent standards for security, resiliency, and regulatory compliance. Their impact will be felt in every microsecond saved and every market opportunity captured, contributing directly to Citi's standing as a premier global equities trading institution.

Technical Responsibilities:

• Design low-latency compute topologies including bare-metal servers, NICs, kernel bypass technologies such as DPDK and Solarflare, and FPGA/co-location hardware


• Evaluate CPU microarchitecture, NUMA topology, cache behavior, and memory bandwidth characteristics for trading workloads


• Define hardware and firmware standards in partnership with vendors including Dell, HPE, Mellanox/NVIDIA Networking, Arista, Cisco, and Juniper


• Design and maintain custom server build patterns tailored to the low-latency trading platform, distinct from Citi's standard enterprise server catalog


• Establish and enforce standards for low latency Linux, Windows, and Microservice infrastructure, including OS optimization, kernel bypass technologies, CPU isolation, NUMA optimization, interrupt tuning, and deterministic performance engineering


• Build repeatable benchmarking harnesses to measure tick-to-trade latency, jitter, and throughput


• Conduct comparative hardware, firmware, and BIOS tuning analysis including CPU pinning, IRQ affinity, C-state/P-state tuning, and huge pages configuration


• Correlate benchmark results with real trading telemetry to validate production readiness


• Drive packet capture analysis and latency telemetry across the full trading stack


• Architect and deliver high-performance colocation environments connecting exchange venues, market data providers,