Senior C++ Developer (Hybrid, UK-Based). Job in London LilyLifestyle Jobs

Location: London

Salary: £80,000 - £100,000 + EMI Share Options + Private Medical Insurance

Vacancy Type: Full-time, Permanent

At Hoptroff, we build nanosecond-accurate, software-driven timing systems used by global investment banks, telecoms operators, and broadcasters – including the MiFID II-compliant trade timestamping that financial regulators depend on. When microseconds aren’t tight enough and milliseconds are an eternity, our software is what’s keeping the world in sync.

We’re entering an exciting phase of growth and looking for a Senior C++ Developer to join our small, high-calibre engineering team. You’ll write modern C++ (C++/23) at the heart of our Linux-based clock and time synchronisation platform – tight, performance-sensitive code where jitter is measured in nanoseconds and correctness is non-negotiable. You’ll own significant components of the platform, contribute to architecture, and work closely alongside a junior developer and a contractor on a tight, collaborative team.

The Role

• Reporting to the Software Development Manager, you’ll lead the design, development, and optimisation of C++ software within our Linux-based timing systems.
• Design, build, and optimise low-latency, high-precision C++ at the heart of our timing products – code where performance, determinism, and jitter really matter.
• Make architectural decisions on systems that have to be correct, fast, and observable in production – balancing maintainability with the hard real-time constraints of precision timing.
• Develop online and offline tooling to support time synchronisation and system monitoring.
• Build and maintain automated test cases using Python-based system test frameworks.
• Provide senior-level technical input across product, QA, hardware, and commercial conversations.
• Share knowledge, review code, and support the development of our junior C++ developer.
• Help shape engineering standards, tooling, and processes.

Essential Experience

• Extensive professional experience writing modern C++ in production – fluent in modern C++ idioms and confident with C++/23 features such as concepts, ranges, coroutines, and constant expressions (constexpr/consteval).
• A track record of delivering low-latency, performance-sensitive systems on Linux – production code where determinism, throughput, and tail latency matter.
• Strong computer science fundamentals: data structures, algorithms, concurrency, performance optimisation.
• Demonstrable ability to design software architecture and make sound technical trade-offs.
• Strong debugging and profiling skills (perf, valgrind, sanitizers, flame graphs) – you’ve cared about cache lines, lock contention, jitter, and tail latency, not just correctness.
• Confident with Git, CI/CD pipelines, modern build tooling (CMake), and automated testing frameworks.
• Clear technical communicator – you can explain trade-offs to engineers and non-engineers alike.

Nice to Have

• Linux networking experience (sockets, networking concepts and standard tooling).
• Experience interacting with hardware on Linux (device drivers, system interfaces, low-level I/O).
• Low-level Windows systems development (Windows APIs, system services, platform-specific debugging).
• PostgreSQL or other relational database experience.
• Python and/or Go (Golang) for tooling, automation, or supporting services.
• Familiarity with time synchronisation protocols such as PTP or NTP.
• Open-source contributions or evidence of staying current with the C++ standard.
• Open to integrating AI tools where they add value.

What We Offer

• Salary of £80,000 - £100,000, depending on experience.
• EMI Share Options.
• Private Medical Insurance.
• Hybrid working – 2 days per week at our London (Shoreditch) office, with regular team events.
• Based at a Shoreditch FinTech incubator – a thriving community of like-minded businesses with a full social calendar, networking opportunities, and (importantly) dog-friendly.
• Your code will sit underneath MiFID II-compliant trade timestamps at major banks, broadcast sync at tier-1 broadcasters, and timing infrastructure at telecoms operators – tangible, high-stakes impact at global scale.
• A team that invests in modern tooling and continuous learning.