About Us PhysicsX is a deep-tech company with roots in numerical physics and Formula One, dedicated to accelerating hardware innovation at the speed of software.

We are building an AI-driven simulation software stack for engineering and manufacturing across advanced industries. By enabling high-fidelity, multi-physics simulation through AI inference across the entire engineering lifecycle, PhysicsX unlocks new levels of optimization and automation in design, manufacturing, and operations — empowering engineers to push the boundaries of possibility. Our customers include leading innovators in Aerospace & Defense, Materials, Energy, Semiconductors, and Automotive.

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.

Note: We are currently recruiting for multiple positions, however please only apply for the role that best aligns with your skillset and career goals.

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 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.

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.

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.
• 5% 401(k) match – invest in your future.
• Flexible working – balance your work and life in a way that works for you.
• Hybrid setup – enjoy our Manhattan office while keeping remote flexibility.
• Enhanced parental leave – support for life’s biggest milestones.
• Private healthcare – comprehensive coverage for you and your family.
• 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.

Salary Range $120,000 - 240,000 depending on experience

Seniority will be assessed throughout our interview process

We value diversity and are committed to equal employment opportunity regardless of sex, race, religion, ethnicity, nationality, disability, age, sexual orientation or gender identity. We strongly encourage individuals from groups traditionally underrepresented in tech to apply. To help make a change, we sponsor bright women from disadvantaged backgrounds through their university degrees in science and mathematics.

We collect diversity and inclusion data solely for the purpose of monitoring the effectiveness of our equal opportunities policies and ensuring compliance with UK employment and equality legislation. This information is confidential, used only in aggregate form, and will not influence the outcome of your application.