Job Description

C++ Developer – High Frequency Trading (HFT Systems)
Join MARGO in the UK (London) – High Performance Trading Environments
MARGO is a tech-native consultancy delivering elite software engineering expertise to the most demanding financial markets environments.We operate in latency-critical trading contexts where performance, determinism and predictability are core system requirements. Our consultants work in highly specialised trading environments, designing systems that interact directly with exchanges and market venues under extreme time constraints.
Business Context
You will join a High Frequency Trading / Low Latency Trading environment within one of our partners (investment banks, proprietary trading firms or market makers).The teams design, build and operate latency-sensitive trading systems directly connected to exchanges, typically deployed in colocated environments.These systems are characterised by:·        Microsecond to sub-microsecond latency constraints·        Deterministic and predictable execution paths·        Minimal software and network overhead·        Direct interaction with market data feeds and order gateways

We are looking for a C++ Software Engineer to work on latency-critical trading infrastructure.The role is strongly engineering-driven and focuses on speed, predictability and control of execution rather than functional feature delivery.Depending on the environment, the role may also involve interaction with C# components used outside the ultra-latency-critical execution path.
Key Responsibilities
Core HFT Engineering·        Design, develop and optimise ultra-low latency C++ trading components·        Work on critical execution paths for market data processing and order routing·        Implement lock-free and wait-free algorithms·        Optimise memory allocation, cache locality and CPU utilisation·        Reduce jitter and tail latency
System-Level & Hardware-Aware Optimisation·        Analyse and optimise CPU behaviour (branch prediction, cache misses, NUMA effects)·        Work closely with infrastructure and network teams on kernel bypass and user-space networking·        Profile systems at instruction-level and hardware-counter granularity
Production Ownership·        Ensure correctness, determinism and stability of production trading systems·        Participate in production releases and live deployments·        Investigate latency regressions and production anomalies·        Maintain rigorous operational discipline
Use of C# (Non-Critical Path)C# may be used outside the latency-critical execution path for:·        Monitoring and control tooling·        Configuration and orchestration services·        Risk guards, limits and kill-switch mechanisms·        Real-time dashboards and operational analytics
C# is not used on the execution path and does not replace core C++ expertise.
Technical Environment
Core Technologies·        Modern C++ (C++17/20)- Lock-free programming  - Custom memory allocators- Zero-copy architectures·        Linux (advanced / low-level understanding)- CPU pinning- Huge pages- NUMA architectures·        Networking- TCP / UDP market data feeds- Multicast- Kernel bypass technologies (DPDK, Solarflare Onload or equivalent)
Latency & Performance Tooling·        CPU profilers and hardware performance counters·        Packet capture and latency measurement tools·        Exchange simulators and market data replay tools
Required Experience & Skills
Essential·        Strong experience in C++ development for performance-critical or low-latency systems·        Proven background in HFT or ultra-low latency trading environments·        Deep understanding of CPU architecture, caches and memory models·        Strong knowledge of concurrency, memory ordering and Linux internals·        Experience working close to hardware and network layers·        Strong production mindset and sense of ownership
Highly Valued·        Exposure to C# in trading, control or monitoring systems·        Experience with market data feed handlers or order gateways·        Prior exposure to market making or proprietary trading environments·        Experience with FPGA-assisted or hybrid architectures
Why Join MARGO
·        Access to elite HFT and ultra-low latency trading environments·        Technically extreme and intellectually demanding engineering assignments·        Clear separation between execution-critical and supporting systems·        Human-sized consultancy with very high technical standards·        Long-term positioning on rare, high-value low-latency engineering skillsets

Important NoteThis role is not suitable for candidates with a C#-only background. Core execution systems are implemented in C++.
Please note - We do not offer visa sponsorship for this position.
Interested? Motivated? Apply on our website or at staff.uk@margo.com

About MARGO

More than a simple IT consulting group, MARGO is an alchemy of talents with constantly enriched expertise, always encouraged to be dynamic and to flourish.

For more than 17 years, we have been carrying out missions of the highest technical complexity, enabling the digital acceleration of our clients, while ensuring a perpetual intellectual and collective stimulation for all our talents.

At MARGO it's Consultant First.

By joining MARGO, your talent today will remain relevant tomorrow. We bring you into the group not only for what you are today but for the potential you wish to develop.

At MARGO, you will be able to build your own path to excellence within our teams and our missions. Tailor-made to serve your ambition and to match your talent.

Today, Margo has over 400 employees in 8 entities:

► MARGO Trading Systems: our full stack development offer in market finance

► MARGO Capital Markets: our business offer in market finance

► MARGO Analytics: our expertise in data science and data engineering

► A CAPELLA Consulting: our business offer dedicated to insurance

► CODE BUSTERS: our community of developers

► DELIVERED by MARGO: our 100% remote full stack development entity

► MARGO UK: expertise in complex coding and application support on the English market.

► MARGO Poland: expertise in complex coding in retail Banking on the Polish market.

Industry

IT & Software

Company Size

201-500 employees

Headquarters

Courbevoie, FR

Year Founded

2005

Website

margo.com

Social Media