Low-Latency Java Architect for Global Finance (Hybrid)

Citigroup Inc.; Greater London; Hybrid; GBP 110,000 - 140,000; Full time

Benefits offered by this job

27 days annual leave

Discretionary bonus

Private Medical Care

Life Insurance

Employee Assistance Program

Pension Plan

Paid Parental Leave

Learning and development resources

Hybrid work up to 2 days per week

Job summary

Citigroup Inc. in London’s technology division is seeking a senior Low Latency Java Engineer to design, implement and optimise high-performance trading systems.

You will work on microservices-based architectures with Java, C++, and Rust, focusing on ultra-fast response times and scalable data handling. Join a specialist team that delivers cutting-edge market tech, mentors engineers, and supports hybrid work.

Qualifications

• Experience in low-latency Java or Rust trading systems.
• Strong knowledge of market data handling and KDB.
• Proven leadership and project delivery skills.
• Excellent communication and ability to mentor juniors.
• Deep understanding of the JVM, Linux, and kernel concepts.

Responsibilities

• Hands-on coding in Java/Rust for low-latency microservices.
• Lead integration of new products and optimize processes.
• Analyze complex business and system processes.
• Provide SME expertise in Java low-latency development.
• Mentor junior developers.

Skills

Java low latency

Algorithmic trading

KDB / Market data

Linux

OpenOnload

Event-sourced microservices

Team leadership

UML diagrams

C++ (nice to have)

TCP/IP networking

Tools

KDB

Solarflare OpenOnload

Job description

Citigroup Inc. in London’s technology division is seeking a senior Low Latency Java Engineer to design, implement and optimise high-performance trading systems.

You will work on microservices-based architectures with Java, C++, and Rust, focusing on ultra-fast response times and scalable data handling. Join a specialist team that delivers cutting-edge market tech, mentors engineers, and supports hybrid work.