Senior Software Engineer

CBSbutler; Greater London; On-site; GBP 70,000 - 110,000; Full time

Job summary

CBSbutler is seeking an experienced Senior Software Engineer to join our London team. You will work on cross‑platform desktop and mobile applications, primarily coding in modern C++, with involvement in design, architecture and end‑to‑end delivery.

You will lead scoping and estimation, drive integration tasks, and champion automated testing and AI tooling to improve speed and quality. Collaboration across a small team will be essential to success.

Qualifications

• Degree in Computer Science, Engineering, or related field.
• Experience building complex software in modern C++ for systems/desktop/mobile apps.
• Design and architecture experience with multi‑component systems and failure planning.
• Strong grasp of concurrency, IPC, networking, security concepts, performance and algorithms.
• Delivery oriented, even without formal delivery management background.

Responsibilities

• Design, implement, and maintain cross‑platform desktop and mobile features for reliable, high‑quality software.
• Lead scoping, design and estimation of software and complex integration tasks.
• Coordinate work across a small team of engineers and remove blockers.
• Drive end‑to‑end integration with hardware, user workflows and enterprise infrastructure.
• Promote code quality, automated testing and AI tooling to speed delivery.
• Provide technical leadership on projects and guide architecture decisions.

Skills

Modern C++

System software

Desktop/mobile apps

Concurrency

Networking

Security concepts

Education

Degree in Computer Science / Engineering

Tools

AI tooling

Job description

My client is seeking an experienced Senior Software Engineer to support their team in London, UK. This role suits a strong senior software engineer who wants to go beyond writing code. You do not need a formal delivery-management background, just solid engineering and an appetite to take on more: design, architecture, coordination, planning and end-to-end delivery.

Key Responsibilities

• Design, implement and maintain features and components for cross-platform desktop and mobile applications, with a focus on reliable, high-quality and highly usable software.
• Write code primarily in modern C++, and work across other languages as the work requires.
• Lead the scoping, design and estimating of new software and complex integration tasks, building prototypes to de-risk the harder ones.
• Use AI tooling to improve development speed and quality.
• Shape and deliver the roadmap for the end-point software, translating company and product priorities into a plan you own and drive.
• Plan and coordinate work across a small team of engineers, removing blockers and keeping momentum.
• Help coordinate delivery across our Hardsec solutions, keeping cross-team dependencies visible and managed.
• Lead the end-to-end integration and test of the software as a component, including its integrations with hardware, with end-user workflow applications on the remote side, and with enterprise infrastructure such as identity providers.
• Drive improvements in code maintainability, automation and supportability, championing code review, automated testing, stable APIs and the use of AI tooling and agentic workflows.
• Provide technical leadership on projects, steering design choices, solving technical issues and guiding others on code quality and testing.

What We’re Looking For

• A degree in Computer Science, Engineering, or a related technical or scientific subject.
• Experience developing complex software in modern C++ for systems software and desktop or mobile applications.
• Design and architecture experience, and the ability to solve systems-level problems with multiple complex interactions between components, including planning for failure.
• A strong grasp of core computer science concepts: concurrency, IPC, networking, security including software exploitation, performance and algorithms.
• A genuine appetite to take on delivery responsibility, even without a formal delivery management background.