Low Latency Trading Infrastructure Engineer

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, and internal trading systems

Implement ultra-low latency Layer 1/Layer 2 network configurations across trading infrastructure

Execute formal certification test plans for new hardware, firmware, and OS/kernel builds before production introduction

Maintain audit-ready certification documentation aligned to internal risk and compliance standards

Coordinate with Risk, InfoSec, and Exchange/Venue technical teams where co-location or vendor certification is required, including adherence to CAT and MiFID II requirements for time synchronization, monitoring, and reporting

Execute infrastructure provisioning and deployments within air-gapped or network-segmented environments with no direct internet access

Manage image and firmware distribution via approved offline or tightly controlled transfer mechanisms

Apply strict change management and rollback procedures given the production sensitivity of the environment

Deploy and support connectivity circuits to external clients and exchanges, including cross-connect provisioning and handoff validation at specialized and co-located data centers

Lead bare-metal automation, deployment pipelines, and infrastructure-as-code practices using tools such as Ansible, Terraform, and Puppet for rapid, repeatable infrastructure delivery

Manage and configure Active Directory, ISA, DNS, PTP, Remote Access Solutions, and infrastructure management and monitoring technologies such as Lenovo LXCA, HPE OneView, Dell OpenManage Enterprise, and HCL BigFix

Monitor compute health, latency drift, and hardware degradation using specialized low-level telemetry tools

Manage hardware lifecycle refresh planning including hardware aging, EOL firmware tracking, and vendor support contract coordination

Troubleshoot at the hardware, OS, and network stack level under time-sensitive, high-impact conditions, often during live market hours

Manage Kubernetes cluster operations and workload orchestration for trading-adjacent microservice infrastructure

Implement and maintain high-speed interconnects including InfiniBand, RDMA over Converged Ethernet (RoCE), and multicast networking protocols

Non-Technical / Leadership Responsibilities:

Collaborate with application development and support teams to optimize end-to-end trading latency and infrastructure determinism

Participate in incident management and infrastructure resiliency efforts for mission-critical trading environments, including structured post-incident documentation and root cause analysis

Maintain close partnership with software delivery teams, Citi's enterprise technology group, and trading functions throughout the end-to-end platform delivery and deployment lifecycle

Produce meticulous documentation to support audit and regulatory review, including change requests, incident reports, and certification approval packages

Represent engineering requirements and infrastructure risk clearly in written communications to cross-functional partners in Risk, InfoSec, and Compliance

Work with vendor partners, exchange providers, and hardware manufacturers to optimize resiliency and performance, maintaining operational coordination with co-location data center facility operators

Support hardware procurement, vendor engagement, colocation buildout activities, and telecom contract processes as an individual technical contributor

Demonstrate composure under pressure given the financial impact of latency or downtime, and willingness to support off-hours maintenance windows and rapid incident response during market-critical periods

Qualifications:

6+ years of hands-on experience in low latency infrastructure engineering within electronic trading, capital markets, hedge funds, trading venues, or equivalent high-performance financial technology environments

Proven, hands-on experience building and operating exchange colocation environments for Equities or multi-asset electronic trading platforms, including physical rack management, cross-connect provisioning, and circuit validation

Deep technical expertise in low latency network architecture, including ultra-low latency switching platforms, multicast market data distribution, and Precision Time Protocol (PTP) implementation and synchronization

Advanced Linux systems engineering proficiency in RHEL and equivalent distributions, with deep hands-on experience in kernel tuning, CPU pinning and isolation, NUMA optimization, interrupt affinity (IRQ), C-state/P-state management, and huge pages configuration

Hands-on experience with kernel bypass and packet acceleration technologies including DPDK, XDP, Solarflare OpenOnload, and FPGA-based NIC solutions, with demonstrated ability to reduce stack-level latency to sub-microsecond levels

Proficiency in scripting and automation using Python, Bash, or equivalent languages, with experience building tooling for benchmarking, telemetry collection, and infrastructure provisioning in air-gapped or tightly controlled environments

Strong experience with infrastructure automation tools including Ansible, Terraform, or Puppet for bare-metal provisioning, firmware management, and repeatable deployment pipelines in trading-sensitive environments

Hands-on experience with CI/CD pipeline design and execution using Jenkins, GitLab CI/CD, GitHub Actions, or ArgoCD, including build, test, and deployment automation for infrastructure-as-code workflows

Experience with container orchestration platforms including Kubernetes (OpenShift or Amazon EKS preferred), including deployment, scaling, node affinity configuration, and low-latency workload scheduling

Proficiency with high-speed interconnect protocols and hardware including InfiniBand, RDMA over Converged Ethernet (RoCE), and multicast networking, applied to market data distribution and inter-system communication

Experience with low-level telemetry and monitoring tooling, including packet capture analysis tools such as Wireshark and tcpdump, hardware performance counters, and latency measurement frameworks relevant to tick-to-trade profiling

Strong understanding of modern low latency hardware platforms, NICs, and FPGA-enabled compute environments, with experience evaluating and benchmarking hardware from vendors including Dell, HPE, Mellanox/NVIDIA Networking, Arista, Cisco, and Juniper

Familiarity with exchange connectivity rules, CAT regulatory requirements, MiFID II time synchronization standards, and internal change-control/compliance frameworks as they pertain to trading infrastructure

Meticulous documentation habits and strong written communication skills for change requests, incident reports, and certification approval packages

Experience supporting hardware procurement, vendor coordination, colocation buildouts, and telecom processes in a financial services context

Education:

Bachelor's degree in Computer Science, Electrical Engineering, Information Technology, or a related technical discipline, or equivalent practical experience in a highly specialized low-latency or high-performance computing environment

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Job Family Group: Technology ------------------------------------------------------

Job Family: Technology Product Management ------------------------------------------------------

Time Type: Full time ------------------------------------------------------

Primary Location: Irving Texas United States ------------------------------------------------------

Primary Location Full Time Salary Range: $138,720.00 - $208,080.00

In addition to salary, Citi’s offerings may also include, for eligible employees, discretionary and formulaic incentive and retention awards. Citi offers competitive employee benefits, including: medical, dental & vision coverage; 401(k); life, accident, and disability insurance; and wellness programs. Citi also offers paid time off packages, including planned time off (vacation), unplanned time off (sick leave), and paid holidays. For additional information regarding Citi employee benefits, please visit citibenefits.com. Available offerings may vary by jurisdiction, job level, and date of hire.

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Most Relevant Skills Please see the requirements listed above. ------------------------------------------------------

Other Relevant Skills For complementary skills, please see above and/or contact the recruiter. ------------------------------------------------------

Anticipated Posting Close Date: Nov 16, 2026 ------------------------------------------------------

Automated Processing and AI

We use automated processing, including artificial intelligence, for our legitimate business interests (or our reasonable and appropriate business purposes) to identify and align the candidate's skills and abilities with a specific job opening. Additionally, if you so choose, or consent, we can match your skills and abilities to other suitable roles at Citi.

Importantly, all our hiring processes and decisions, including determining your suitability for a role, are conducted, checked, and decided by individuals. Our automated processing and AI do not involve relying on automatic or autonomous decision-making. Please refer to any Jurisdictional Considerations, with specific provisions for your country (where relevant) for further details.

Illinois residents – AI Notice and Right

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