Software Engineer, Libraries

PhysicsX is a deep-tech company of scientists and engineers, developing machine learning applications to massively accelerate physics simulations and enable a new frontier of optimisation opportunities in design, engineering, and systems control. We help our customers fundamentally improve their concepts and designs, transform their engineering processes and drive operational product performance. We do this in some of the most advanced and important industries of our time – including Renewables & Sustainability, Space, Aerospace, Medical Devices, Additive Manufacturing and Energy. Our work creates positive impact for society, be it by improving the design of artificial hearts, reducing CO₂ emissions from aircraft and road vehicles, or increasing the performance of wind turbines.

The Role

PhysicsX is developing a platform used by Data Scientists and Simulation Engineers to build, train and deploy Deep Physics Models. The core of this platform is powered by several Machine Learning Python Libraries handling everything from data processing, to deep learning model training, and complex optimisation algorithms. The Libraries team is responsible for designing, developing, and maintaining those Machine Learning Libraries. As a Software Engineer within the team, you will focus on the underlying engineering that makes our libraries fast, scalable, and a pleasure to use. You are a software craftsperson who champions best practices, ensuring that our entire development lifecycle—from code design to CI/CD—is robust and maintainable. Your work provides the solid foundation upon which our machine learning innovations are built.

What you will do

• Collaborate with product managers, machine learning engineers, and library users to translate functional requirements into robust technical specifications and production-ready code.
• Architect, build, and maintain the foundational software of our internal Machine Learning libraries, with a relentless focus on performance, and scalability.
• Contribute high-quality, tested, documented, and maintainable code across the library stack, ensuring our core systems are reliable and easy for other engineers to build upon.
• Champion software engineering excellence across the team and company, driving best practices in testing (unit, integration, performance), CI/CD, and system architecture.
• Own your work end-to-end, from ideation and experimentation through to deployment and maintenance in a small, agile team environment.
• Continuously explore and evaluate new techniques and frameworks, helping to guide the technical evolution of our platform.
• Share your knowledge with the team, contribute to our engineering guild, and stay connected with the broader community.

What you bring to the table

• A passion for the craft of software engineering and building robust, maintainable systems in a collaborative, cross-functional team.
• Solid software engineering skills, with a focus on writing clean, testable, and maintainable code.
• A commitment to owning the software development lifecycle, including testing, containerization, and CI/CD.
• Expert-level proficiency in modern Python, with a deep understanding of its performance characteristics, design patterns, and packaging.
• Familiarity with building performant and reliable Python systems, including low-level C/C++ extensions (e.g., using pybind11, Cython) and instrumentation for production telemetry (e.g., Prometheus, OpenTelemetry).
• A proactive ownership mindset and the ability to navigate ambiguity.
• Excellent collaboration and communication skills for working effectively with teams and stakeholders.

Ideally

• Professional experience GPGPU programming (e.g., CUDA, Triton) for performance optimization.
• Experience building and maintaining widely-used internal or open-source libraries.
• Familiarity with the machine learning development lifecycle and core concepts (e.g., bias-variance tradeoff, common optimizers).
• Familiarity with 3D geometric data structures and algorithms.

What we offer

• Equity options – share in our success and growth.
• 10% employer pension contribution – invest in your future.
• Free office lunches – great food to fuel your workdays.
• Flexible working – balance your work and life in a way that works for you.
• Hybrid setup – enjoy our new Shoreditch office while keeping remote flexibility.
• Enhanced parental leave – support for life’s biggest milestones.
• Private healthcare – comprehensive coverage.
• Personal development – access learning and training to help you grow.
• Work from anywhere – extend your remote setup to enjoy the sun or reconnect with loved ones.

Our stance

We believe diversity fuels innovation, and we're building a culture where everyone belongs. We're proud to be an equal opportunity employer, welcoming talent of all backgrounds, identities, and experiences. Changing the face of tech takes action, which is why we actively encourage individuals from historically underrepresented groups to apply.