Senior Low Latency Java Engineer

Citi; Greater London; On-site; GBP 120,000 - 180,000; Full time

Job summary

Citi in London is seeking a Senior Low Latency Java Engineer to lead development of high-performance trading applications and frameworks. The role sits in the HPA team, focusing on Java-based microservices and low-latency design across Citi’s trading platforms.

You will work with market data handling, time-series databases like KDB, and mentor junior developers while collaborating with senior stakeholders to modernise and optimise the trading infrastructure.

Qualifications

• Bachelor's degree or equivalent required.
• Senior level with extensive low-latency experience.
• Experience in algorithmic trading and market data handling.
• Strong leadership and collaboration skills.
• Proven Java low-latency development expertise and microservices.
• Deep knowledge of Java/JVM and Linux.
• Familiarity with TCP/IP and kernel bypass.
• Ability to analyze complex processes and design scalable solutions.

Responsibilities

• Hands-on Java development in a low-latency environment (70% of time).
• Lead integration of functions to meet goals and deploy new products.
• Analyze complex business and system processes to define solutions.
• Provide expertise in Java low-latency development.
• Consult with end users to capture specifications and inform design.
• Influence senior leaders and liaise with external parties.
• Assess risk and ensure compliance with policies and regulations; escalate as needed.
• Mentor junior developers and support/coach peers.

Skills

SME in Applications Development

Algorithmic Trading (low latency)

Market Data handling (KDB)

Leadership & project management

Java low-latency frameworks

Java, JVM, Linux

TCP/IP & kernel bypass (OpenOnload)

Performance tuning

Architecture/design

UML diagrams

Communication & EQ

Mentoring juniors

C++ (nice to have)

Education

Bachelor's degree

Tools

C++

Job description

Senior Low Latency Java Engineer

This 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 of this role is to lead applications systems analysis and programming activities.

The role is to provide senior, low-latency systems and application framework engineering (skilled in Java, C++, KDB, market data, algorithmic trading technology) within the London Based High Performance Architectures (HPA ) team. The team require a specialist on algorithmic trading systems utilities including but not limited to market data replay and back test/simulation utilities. The HPA organisation are a high skilled 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 eTrading platforms in Markets Technology.

Responsibilities

• 70% hands in the Java codebase. We build microservices based event sourcing systems on a low latency in-house framework. Response times in the 10 microsecond to 100 microsecond range.
• Lead integration of functions to meet goals, deploy new products, and enhance processes
• Analyze complex business processes, system processes, and industry standards to define and develop solutions to high level problems
• Provide world-class expertise in area of Java low latency development.
• Utilize 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 into overall system design
• Influence and negotiate with senior leaders and communicate with external parties
• 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 behaviour, conduct and business practices, and escalating, managing and reporting control issues with transparency.
• Happy to work with and educate and support/mentor Junior developers and less experienced senior Java developers.

Skills and Experience

• Demonstrated Subject Matter Expert (SME) in area(s) of Applications Development
• In-depth experience with Algorithmic Trading application development, preferably in low latency environment
• Detailed comprehension and experience with Market Data handling and associated technologies (such as time-series databases e.g. 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 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++

Education / Qualifications

• Bachelor's degree/University degree or equivalent experience in a similar role.

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