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PhysicsX is the physics AI company for industrials. The company’s mission is to accelerate hardware innovation by overhauling what industrial engineering and manufacturing look like today. PhysicsX is building a new simulation software stack to deliver deep physics AI enablement across the entire engineering lifecycle. The company partners with leading organisations in aerospace & defence, automotive, semiconductors, materials, and energy & renewables, supporting them on some of their most critical and complex challenges. PhysicsX is headquartered in the United Kingdom, with offices in London, New York, and Singapore and an expanding presence in the Bay Area.
The Role
As a Principal Security Engineer, you will partner closely with engineering teams to design and implement secure development practices, integrate security into our CI/CD pipeline, and lead security and design reviews.
You’ll bring deep expertise in DevSecOps, application security, hands-on experience securing web applications and APIs, and a strong understanding of modern development workflows. This is a unique opportunity to shape the future of our security program while working in a high-ownership, high-impact environment.
What you will do
- Architect and integrate security tooling directly into CI/CD pipelines to automate the detection and prevention of vulnerabilities, ensuring "shift-left" security at scale.
- Lead threat modeling and secure design reviews for web applications, APIs, and cloud services.
- Oversee the end-to-end product vulnerability lifecycle, from issue triage, prioritization, remediation support, with clear risk communication.
- Drive secure coding standards, develop playbooks, and provide hand-on training and mentorship to instill a security-first mindset across the organization.
- Design and scale secure development practices by collaborating cross-functionally with engineering teams throughout the entire software lifecycle.
- Engage with customers during security reviews
What you bring to the table
- 10+ years in security, with a focus on DevSecOps and security design reviews
- Hands-on experience with secure coding, OWASP Top 10, threat modeling, and SDLC integration
- Experience with GitHub/GitLab, CI/CD, IaC, and containerized environments
- Experience deploying and working with SAST tooling (e.g. Semgrep, Snyk)
- Experience developing in Python and Go.
- Track record of balancing pragmatism and security rigor in a fast-paced setting
- Strong communication skills
Nice to Have Skills
- Understanding of AI security fundamentals and how application security and AI security intersect
- Experience securing cloud infrastructure
- Participation in bug bounty programs and managing security disclosure
- Familiarity with the BSIMM framework
- Experience in cloud security including identity and access management and cloud-native services.
What we offer
Build what actually matters
Help shape an AI-native engineering company at a formative stage, tackling problems that genuinely matter for industry and society. This is work with real-world impact - and something you can be proud to stand behind.
Learn alongside exceptional people
Work with a high-caliber, collaborative team of engineers, scientists, and operators who care deeply about doing great work, and about helping each other get better. We come from diverse backgrounds, but we share a commitment to operating at the highest level and addressing some of the most complex challenges out there. If you’re ambitious, thoughtful, and driven by impact, you’ll feel at home.
Influence over hierarchy
We operate with a flat structure: good ideas win - wherever they come from. Questioning assumptions and challenging the status quo isn’t just welcomed, it’s expected.
Sustainable pace, long-term ambition
Building meaningful technology is a marathon, not a sprint. We believe in balancing focused, ambitious work with a life beyond it. Our hybrid model blends time together in our New York office with work-from-home days, giving you the flexibility to work sustainably while staying connected in person.
UK Benefits:
Equity options; 10% pension employer contribution; 25 days holiday plus public holidays; private health insurance; enhanced parental leave; free lunch onsite
US Benefits:
🚀 Equity options - share meaningfully in the company you’re helping to build.
💰 5% contribution to 401(k) - build long-term security with a strong retirement plan.
🍽️ Free team lunch 1x/week - good food, great company, and space to connect.
🏥 Private health insurance – comprehensive cover for you, offering total peace of mind.
👶 Enhanced parental leave – 3 months full pay paternity and 6 months full pay maternity leave, to provide extra flexibility during the moments that matter most.
☀️ 20 days of Annual Leave (+ Public Holidays) - because taking time to rest matters.
📈 Personal development – dedicated support for learning, development, and leveling up over time.
💪 Gympass / Wellhub (subsidized) – for you and up to 3 family members, supporting both physical and mental wellbeing.
💳 Flexible Spending Account (FSA) – set aside pre-tax dollars for eligible healthcare expenses.
🔎 Watch this space, we’re continuing to build this as we grow…
Salary for this position in the USA is from $200,000 to $300,000
Skills Required
- 10+ years of experience in security, focused on DevSecOps and security design reviews
- Hands-on experience with secure coding, OWASP Top 10, threat modeling, and SDLC integration
- Experience with GitHub or GitLab, CI/CD, Infrastructure as Code, and containerized environments
- Experience deploying and using SAST tooling such as Semgrep or Snyk
- Experience developing in Python and Go
- Ability to balance pragmatism and security rigor in a fast-paced environment
- Strong communication skills
- Understanding of AI security fundamentals and the intersection of application security and AI security
- Experience securing cloud infrastructure
- Participation in bug bounty programs and managing security disclosure
- Familiarity with the BSIMM framework
- Experience with cloud security, including identity and access management and cloud-native services
What We Do
PhysicsX is a deep-tech company of scientists and engineers, developing machine learning applications to accelerate physics simulations and enable a new frontier of optimization opportunities in design and engineering. Born out of numerical physics, we help our customers radically 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 Space, Aerospace, Medical Devices, Additive Manufacturing, Electric Vehicles, Motorsport, and Renewables. Our work creates positive impact for society, be it by improving the design of artificial hearts, reducing CO2 emissions from aircraft and road vehicles, and increasing the performance of wind turbines. We are currently recruiting for multiple positions, however please only apply for the role that best aligns with your skillset and career goals. We do not currently offer work experience
