Senior Low Latency Engineer

Senior Low Latency Engineer

Job Req Id:

Location(s): London, England, United Kingdom

Job Type: On-Site/Resident

Posted: May. 07, 2026

Job Overview

Senior Low Latency Engineer – Engineer the future of global finance. Our Tech team supports finance by redefining it. Each day, $5 trillion crosses our network. We operate in 180+ countries at a scale few match. From advanced AI deployment to shaping global markets, we build systems that matter. The role is a senior‑level position responsible for establishing and implementing new or revised application systems and programs in coordination with the Technology Team. The overall objective is to lead application systems analysis and programming activities.

The role is to provide senior low‑latency systems and application framework engineering (skilled in Java, C++, Rust, KDB, market data, algorithmic trading technology) within the London‑based High Performance Architectures (HPA) team. The team requires a specialist on algorithmic trading systems utilities, including market data replay and back‑test/simulation utilities. The HPA organization is an enablement group of subject‑matter experts who produce application frameworks and engage with application engineers to enable application modernisation to over 100 teams across Citi with a concentration on low‑latency e‑Trading platforms in Markets Technology.

Responsibilities

• 90% hands‑on work in the Java or Rust codebase, building microservices‑based event‑sourcing systems on a low‑latency in‑house framework with response times in the 10 µs to 100 µs range.
• Lead integration of functions to meet goals, deploy new products, and enhance processes.
• Analyse complex business processes, system processes, and industry standards to define and develop solutions to high‑level problems.
• Provide world‑class expertise in Java low‑latency development.
• Utilise advanced knowledge of supported main system flows and comprehensive knowledge of multiple areas to achieve technology goals.
• Consult with end users to identify system‑function specifications and incorporate them into overall system design.
• Influence and negotiate with senior leaders and communicate with external parties.
• Educate and support/mentor junior developers and less experienced senior Java developers.

Key Skills and Experience

• Demonstrated subject‑matter expert (SME) in applications development.
• In‑depth experience with algorithmic trading application development, preferably in a low‑latency environment.
• Detailed comprehension and experience with market data handling and associated technologies (e.g., time‑series databases such as KDB).
• Demonstrated leadership, project management, and development skills.
• Passion for coding excellent, commercial‑grade, mission‑critical Java frameworks based on event‑sourcing microservices.
• Complete knowledge of modern Java, the JVM, the Linux operating system, system calls, and the kernel.
• Knowledge of TCP and other IP‑based network protocol technologies, including hardware‑accelerated kernel bypass (e.g., Solarflare OpenOnload).
• Performance assessment and targeted tuning.
• Design and architectural elegance.
• Experience in implementing projects.
• Great communicator with high EQ.
• Ability to occasionally produce clear diagrammatic documentation and model key aspects in UML sequence diagrams.
• Relationship and consensus‑building skills.

Nice to Have

• Background in C++.

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

Benefits

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 (annually reviewed) and enjoy a host of additional benefits such as:

• 27 days annual leave (plus bank holidays)
• Discretionary 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

Equal Opportunity Statement

Citi is an equal‑opportunity employer, and qualified candidates will receive consideration without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, disability, status as a protected veteran, or any other characteristic protected by law.

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