C++ Engineer

Ncounter Limited; Greater London; Hybrid; GBP 90,000 - 130,000; Full time

Job summary

Ncounter Limited in London is seeking an experienced Software Developer with strong C++ skills to help build high-performance, low-latency trading systems. You will work on matching engines, FIX gateways, real-time data processing, and collaborate across trading, product and infra teams; hybrid work model with on-site days.

The role requires 5+ years in software development and proven multithreading, Linux, and networking proficiency.

Qualifications

• 5+ years of professional software development experience.
• Strong C++ development skills, ideally alongside commercial Java experience.
• Hands-on FIX protocol experience within electronic trading.
• Experience building low-latency, high-frequency or performance-critical systems.
• Strong Linux knowledge covering multithreading, sockets, IPC and system-level behaviour.
• Good understanding of concurrency, memory management and in-memory optimisation.
• Knowledge of NUMA architectures and performance-focused programming techniques.
• Experience with networking protocols including TCP/IP, UDP, unicast and multicast.
• Python, SQL and relational database experience would be useful.

Responsibilities

• Designing and developing high-performance matching engines, FIX gateways and electronic trading applications.
• Building low-latency, multithreaded systems using C++ and Java.
• Processing real-time market and trading data through highly available systems.
• Developing efficient in-memory data structures, lock-free queues and circular buffers.
• Working with TCP/IP, UDP, multicast and other networking technologies.
• Troubleshooting, profiling and optimising performance-critical production applications.
• Supporting automated testing, DevOps practices and CI/CD pipelines.
• Working closely with trading, product and infrastructure teams throughout the development lifecycle.

Skills

C++

Java

Low-latency

Multithreading

Linux

Networking

FIX protocol

Python

Job description

Software Developer, C++ / Electronic Trading London | Hybrid | Permanent

Ncounter is supporting the growth of a specialist electronic trading technology team responsible for building and enhancing high-performance systems operating across global financial markets. We are looking for an experienced Software Developer with strong C++ skills and a background working on low-latency trading technology.

You'll work on business-critical applications including matching engines, FIX gateways and real-time trading systems, where performance, availability and efficient processing are fundamental. This is a hands‑on development role with considerable exposure to C++, alongside Java, Python and JavaScript within a predominantly Linux environment.

What you'll be working on

• Designing and developing high-performance matching engines, FIX gateways and electronic trading applications
• Building low-latency, multithreaded systems using C++ and Java
• Processing real-time market and trading data through highly available systems
• Developing efficient in‑memory data structures, lock‑free queues and circular buffers
• Working with TCP/IP, UDP, multicast and other networking technologies
• Troubleshooting, profiling and optimising performance‑critical production applications
• Supporting automated testing, DevOps practices and CI/CD pipelines
• Working closely with trading, product and infrastructure teams throughout the development lifecycle

What we're looking for

• 5+ years of professional software development experience
• Strong C++ development skills, ideally alongside commercial Java experience
• Hands‑on FIX protocol experience within electronic trading
• Experience building low‑latency, high‑frequency or performance‑critical systems
• Strong Linux knowledge covering multithreading, sockets, IPC and system‑level behaviour
• Good understanding of concurrency, memory management and in‑memory optimisation
• Knowledge of NUMA architectures and performance‑focused programming techniques
• Experience with networking protocols including TCP/IP, UDP, unicast and multicast
• Python, SQL and relational database experience would be useful

This is an opportunity to work close to the core of electronic trading, solving challenging engineering problems where software performance has a direct business impact.